Migration plays an important role in the UK economy and society and affects many areas of public policy. To understand its impacts and to plan policy, we need accurate and timely data. Without good data on migration and the characteristics of the UK population, many activities become harder—from setting budgets and planning public services to understanding how asylum and visa policies affect migrants and communities.
At the same time, it isn’t enough for the government to simply hold data internally. Publishing trustworthy data on migration allows public scrutiny. Migration figures are also useful to people in many other areas besides central government, such as local government, charities, think tanks, Parliament, and the private sector.
There will always be differences of opinion about exactly what data should be published—and what should be collected at all. Data collection and processing require public resources, so there is a balance to be struck. But this can leave the evidence base feeling unfurnished in some areas. The focus of this piece is to map out where we think these areas currently are.
While having more and better evidence will strengthen the basis for public debate and policymaking on migration, it cannot tell migration policymakers precisely what to do. Such decisions require government to balance competing impacts and interests. This an inherently political exercise requiring value judgments. In line with the mission of the Migration Observatory, the aim of this report is to inform and promote a stronger evidence base for debate, not to say what policy should be.
What did we find?
Overall, the UK has an impressive suite of immigration statistics which has grown and improved over time. There have been many welcome developments, such as a new initiative to link Home Office and HMRC records to understand visa-holders’ earnings, and recently developed statistics on how asylum seekers originally entered the UK.
That said, collecting and managing immigration data has never been an easy task, and there are still gaps and quality issues which reflect structural and long-term problems with data siloes, disorganised databases and failures to keep complete records on some immigration processes.
One of the recurring themes is a lack of linkage between different types of immigration records, which makes it difficult to get a full picture of how a person progresses through the immigration system. The Home Office’s ‘migrant journey’ data is very good at this for more ‘straightforward’ visa routes—such as a person coming to the UK as a skilled worker and later settling permanently—but nothing gives us a complete picture for people who deviate from the main or regular pathways. For example, we lack complete data on how people come to be living in the UK without authorisation, how people move between the asylum, modern slavery, and human-rights related immigration routes, or what happens to asylum seekers who are refused but not returned. One cross-cutting data gap is that there is no record of how often and in what context human rights-based (ECHR) claims are made in the immigration context.
The lack of linkage with non-migration-specific datasets also leaves other policy questions unanswered. Although it is possible for individual-level immigration records to be linked with other databases, such as HMRC payroll data and DWP data on universal credit, this is not done on a routine basis or with complete accuracy. Despite public and political attention on the impacts of migration, relatively little can be said about outcomes for migrants from the main datasets on crime, justice, schooling, and welfare.
Another overarching and long-running issue is the uncertainty of official estimates of migrant populations and flows—in other words, basic statistics on who is entering and leaving the UK and how many people living here have previously migrated. Not having a reliable population estimate, especially for small areas, and for specific migrant groups and nationalities, leaves us with a troubling lack of context for other statistics.
The rest of this briefing covers these data gaps, which have been divided across ten themes, and offers suggestions for solutions.
What do we mean by “problems in the evidence base”?
This report sets out our view of the ten most significant problems, some of which relate to an absence of data and others to quality issues with data which is routinely published. Although they are in the form of a list, the problems are not ranked in order of importance. In the end, our list is necessarily subjective as different experts may identify slightly different issues.
We have tried to identify in each case whether the data is collected and not published, or whether it is a case of data not being collected in the first place. We also try to offer practical suggestions for improvement, while recognising that some will be easier to implement than others. We focus on current problems and recognise that work is underway that aims to address some of the issues (such as the ONS’s population and migration statistics transformation).
What are the main problems in the evidence base now?
- There is inadequate data about migrants’ economic outcomes and how they change over time
More… - More accurate data on the population by nationality and immigration status is needed
More… - There is inadequate information about what happens to people claiming asylum before or after they make their initial claim
More… - There isn’t enough clarity about how many migration cases are affected by human rights laws
More… - There are gaps in the data about immigration enforcement and returns
More… - The size of the unauthorised population is unknown
More… - Data about who is migrating to and from the UK is insufficient to properly understand population change
More… - Official data on migration and crime is full of holes
More… - Local migration figures don’t give us a clear or coherent picture
More… - There is not enough information about the impact of migration on public services or on government spending
More…
There is inadequate data about migrants’ economic outcomes and how they change over time
Most migrants arriving in the UK have at least some work rights, even if they are not main applicants on a work visa. The work migrants do is crucial to their economic impacts, well-being and integration in the UK.
But the data on migrants’ outcomes faces serious limitations. The Labour Force Survey—the main survey giving official data on employment in the UK—has seen its response rate go down sharply in recent years, meaning that it is less representative of the UK population. While the survey can still produce some useful statistics, fine-grained analysis on the outcomes of specific migrant groups is much less reliable.
Government analysts have recently started to match up administrative data on payrolled employments with visa records to find out about migrant employment and earnings (for example, in an ad hoc study of people on the Graduate Route.) They’ve also carried out some one-off surveys to understand the working patterns of particular migrant groups, such as Skilled Workers and Ukrainians. But it remains very difficult to do any structured analysis of the employment rates and earnings outcomes of people who come on work visas, as students, family migrants, or refugees.
For example, many people migrated to the UK as dependents of main visa holders between 2021 and 2023. Adult dependants can work in any job, at any skill level, yet there is no systematic way of understanding whether they work and what they do. One-off studies have provided some information on dependants, such as a Home Office analysis of earnings and employment of certain visa holders using HMRC data, but regular analysis could help us understand the situation better.
Not knowing about the employment status and type of work being done by migrants on specific routes makes it hard to estimate the impact of policy changes. For example, at the time the government brought in a restriction on most international students bringing dependents, no data was available to judge the labour market or fiscal impact. And amidst debates about when and whether migrants should receive Indefinite Leave to Remain (ILR), there is no usable data on whether or how migrants’ employment outcomes change after receiving permanent status.
Related briefings:
- Migrants in the UK Labour Market: An Overview
- Work visas and migrant workers in the UK
- Upward mobility? Earnings trajectories for recent migrants
More accurate data on the population by nationality and immigration status is needed
The census, last carried out in 2021 (2022 in Scotland) provides a detailed snapshot of the population by country of birth and passports held. In between censuses, which are usually held every ten years, the Office for National Statistics (ONS) used to publish regular, fairly detailed estimates of the migrant population. It has not done so since 2021, which has left a problematic gap in UK statistics. The ONS has plans to bring this back when it has fully developed a new method; however, it is not clear yet what level of detail will eventually be provided.
Not having robust data on the migrant population, either at the national or local level, means we lack a ‘denominator’ to put other data about migrants into context. Data on specific populations is often needed to interpret other government statistics. For example, we now have more data than previously on Universal Credit claims from non-UK citizens with particular immigration statuses. However, if we do not know precisely how many EU and non-EU citizens (for example) are living in the country, it is hard to say whether these numbers are high, low, or roughly as expected. A similar argument applies to data on criminal convictions and incarceration by nationality.
A related issue is that there is no comprehensive data on the immigration statuses of people resident in the UK. The Home Office’s Migrant Journey dataset comes closest to this, but only captures visas granted since 2005 and has some gaps. The immigration statuses that migrants hold can affect their outcomes in employment, as covered in the previous section, and in many other areas. Policy changes will often affect people differently depending on their immigration status, but it is hard to model what these effects might be without reliable numbers.
One example of this is a broad category of people who are on temporary visas and who don’t have access to most state benefits—this situation is referred to as having ‘no recourse to public funds’ (NRPF). Until recently, there was almost no statistical evidence at all on people with NRPF, and what is available now remains limited. We can approximate their number using the Migrant Journey data, but say very little about their circumstances, including whether they are on a low income or even a rough idea of where they live. If local authorities were to start publishing the number of people with NRPF that they support, as has been done periodically in Scotland, this would at least partly fill in the picture.
We also only have a rough idea of how many people are on different pathways to settlement (the right to permanent residence). We can’t say precisely, for example, how many people are currently on different types of temporary visa and who might be affected by new plans to increase the standard residence requirement for settlement to 10 years.
Related briefings:
- Migrants in the UK: an Overview
- Deprivation and the No Recourse to Public Funds (NRPF) condition
- Migrant settlement in the UK
There is inadequate information about what happens to people claiming asylum before or after they make their initial claim
Data on the asylum system has improved in recent years. For example, we now have regular data on asylum claims from people arriving by small boat and new breakdowns of the number of people in hotel accommodation. Nonetheless, data gaps still make it hard to get a full answer about how the asylum system works.
First, we know little about the immigration history of people who apply for asylum. In August 2025, the Home Office started publishing data on asylum seekers’ routes of entry to the UK, including a broad breakdown of visa type, which is very helpful for understanding recent trends. But questions remain which the data does not yet answer, such as how long people have been in the UK for already when they claim asylum and how these entry routes look for all nationalities, as opposed to a selection.
Second, a clearer picture of applicants’ journey within and after the asylum system is needed. For example, some people apply for asylum more than once (e.g. by making “further submissions”), and it is not clear how many ultimately receive status through this process, or how long that takes. Some have their claims withdrawn but later re-enter the system, but there is no clear picture from the available sources of what happens to them. There are figures showing the number of people who appeal against a refusal, and the number recorded leaving the UK, but we know much less about those who remain in the UK after a refusal or withdrawn application. Those who are granted status must leave their accommodation and can end up falling under the care of local authorities to prevent homelessness – we have data on this for England, but not for other parts of the UK.
As of June 2024, there were 138,000 people in the broad category of having been refused asylum at initial decision. However, we don’t know how many were still waiting for the result of an appeal, how many had applied to stay in the UK on other grounds (such as the right to family life), how many were cooperating with action to remove them, and how many had lost contact with the Home Office and remained in the UK.
Third, there are several things we don’t know about how well the asylum system is performing. The official statistics show a large proportion of asylum seekers waiting over a year for an initial decision, but it would be helpful to know how common it is for people to wait multiple years (data the Home Office holds). We also don’t know exactly how many asylum cases are waiting to be heard at tribunals, as these are combined with other immigration appeals in the statistics, nor do we have any statistics on legal representation at asylum appeals. Costs associated with asylum hotels and other accommodation are published infrequently and without much detail, such as regional or local variation, as is data on other spending, such as grant funding for Ukrainians and resettled Afghans.
Related briefings:
There isn’t enough clarity about how many migration cases are affected by human rights laws
People can often appeal against immigration decisions, including orders for them to leave the UK, on human rights grounds. These grounds include the right to family life and freedom from torture or inhuman or degrading treatment (Articles 8 and 3 of the European Convention on Human Rights). Legal challenges have received significant attention in recent years, and yet we don’t have a clear understanding of how often and in what way they are used.
We know from tribunal statistics that the broad category of ‘human rights cases’ accounted for over a third (36%) of immigration appeals made between 2015/16 and 2024/25 and that, on average, 18,300 appeals of this kind are heard per year. Beyond this, nothing is published as to what people are appealing against – this could be a refused residence application, or an instruction to leave the UK, or on what grounds. No regularly published figures exist on the immigration status of people making legal challenges, or how many human rights appeals or grants involve people with a refused asylum claim, visa overstayers, or foreign national offenders. Individual court records often contain this level of detail – but the statistics offer no useful breakdown at scale.
For example, the Home Secretary reported in June 2025 that one-third of successful immigration appeals were under ‘exceptional’ circumstances, which rested on human rights claims. More detailed published data on this would enable a fuller understanding.
When people receive immigration status on human rights grounds, there is little information on their journey through the immigration system. As of March 2025, there were roughly 200,000 people on a ten-year path to settlement on human rights grounds, but it is not clear why few people gain settlement on ten-year routes (for example, whether they leave and re-enter the route multiple times, or remain on the route without applying for settlement, perhaps because they cannot afford the fee).
A twenty-year route to settlement also exists for people who have lived in the UK legally or without authorisation for that length of time. No data is published on how often this route is used and by whom.
Related briefings:
There are gaps in the data about immigration enforcement and returns
People who do not have permission to be in the UK are expected to leave, and their return may be enforced. There is more we could know about this area, including how many people have been told to leave the country but are still here, what enforcement actions are conducted and with what outcomes.
In 2020, a government audit found that the Home Office held a database of ‘known individuals’ that it was seeking to remove and estimated that immigration enforcement was handling between 240,000 and 320,000 cases per year. Separately, the Home Office has published snapshots of information on people affected by ‘compliant environment’ measures, showing that some people appear to move in and out of legal status. These were one-off figures. More regular data on the numbers of people subject to immigration enforcement action and their characteristics would help understand how the enforcement system functions.
Similarly, limited information exists on why people are liable for return or deportation. The government publishes return statistics broken down by whether those returned had committed crimes in the UK and the number returned after unsuccessfully applying for asylum. It also publishes figures showing how many small boat arrivals are returned, but beyond this, its broader data on returns does not show how other returnees arrived, be that by other unauthorised routes or with authorisation such as a visa which they may have overstayed or breached (by, for example, working more hours than the visa allows). No data is available on how long those returned had lived in the UK, and their previous immigration statuses.
As for the process, we also don’t know how long it takes to return people, or what proportion of attempts to remove people are ultimately successful. Little is published on legal challenges to return and how many and which types of challenges are more or less likely to be successful, despite these often being cited as a barrier to return.
Most people returned from the UK leave voluntarily. This includes many people who leave without having any contact with the government; in these cases, we do not know whether the person overstayed by a few days or by several years, and this would greatly affect how we interpret the figures. In other voluntary return cases, it has been increasingly common now for the returnee to be ‘assisted’ by being given money or something else which will help them to reestablish a livelihood in the place they’re returning to. Beyond the basic numbers, we don’t know what type and amount of assistance people received, and how much is spent overall on these reintegration schemes.
The government has the power to detain people prior to removal. Detention data has improved significantly over the years, but there are some important things we don’t know about the detention process. This includes how many times people enter and leave detention before they are ultimately removed, or what total length of time this amounts to.
Related briefings:
The size of the unauthorised population is unknown
Another population who we don’t know much about are people living in the UK without permission, or, in other words, the unauthorised (or irregular, or illegal) migrant population. The Home Office last commissioned an estimate of the size of the unauthorised population in 2001 and has stated recently that it can’t currently produce an accurate update. Academics have made various estimates in recent years, but the methods used to do this have their limitations.
Even if measuring the total unauthorised population will always be a challenging task, it would be possible to build a much better picture of specific groups within it. One group within the unauthorised population is refused asylum seekers who have not left the UK. The Home Office’s figures on this population are known to have data quality issues and likely overestimate the true number.
Another group with unauthorised status is people who stay in the UK after their visa or leave entitlement has expired (‘visa overstayers’), or after an extension application is refused. The government does not know with any degree of accuracy how many visa overstayers there are in the UK because there are significant flaws in its system for matching arrivals to departures. It used to publish ‘exit checks’ statistics, which gave an indication of what proportion of people overstayed, but the last edition of these was for the year ending March 2020. The Home Office’s main border control database still suffers from missing travel data and failures in matching departures to arrivals.
In addition, some people can cycle in and out of legal status while remaining in the UK. The Home Office does not routinely track this, although it has conducted one-off studies.
The Home Office improving its borders and immigration data and ensuring this is well linked with visa and asylum records would go some way towards achieving a more accurate picture of how many people are in the UK without authorisation at a given time.
Related briefings:
Data about who is migrating to and from the UK is insufficient to properly understand population change
Policymakers need to know how many people are migrating to and from the UK each year, to understand the size of the population and make short- and long-term plans in areas like healthcare, housing, education, and overall spending.
Estimates of non-EU immigration and emigration have greatly improved in recent years, since the ONS moved from measuring migration primarily through a survey to using administrative data (such as visa data). But the ONS’s new method is still in development and does not yet provide a comprehensive picture.
The figures on British citizens emigrating and returning to the UK are particularly uncertain because ONS does not have a direct measure of migration and instead relies on tax and benefits records to determine if people are still in the country. More work will be needed to be confident that its measures genuinely reflect migration and are not picking up significant shares of people who enter and leave the tax and benefits system without entering or leaving the country.
Changes to the method have led to large upwards revisions in non-EU migration estimates in recent years (notably from 2021 to 2024). Some of these were one-off changes that will not be required again. However, smaller revisions are inevitable because ONS still has to rely on assumptions about the proportion of people who leave before their visa expires, which may become inaccurate when behaviour is changing, at least when producing initial estimates.
Some types of migration are still not captured properly, such as non-EU visa overstayers and the migration of people with Indefinite Leave to Remain (ILR). The ONS’s new method relies on Home Office border data, but this does not provide complete coverage of people entering and exiting the country. Issues such as people exiting the UK on one passport and entering on another, and people crossing via the Common Travel Area, still pose problems for efforts to track individuals coming and going. Missing a relatively high share of travel events can have a big impact on the accuracy of statistics.
There is also no regularly published data on short-term migration, despite substantial numbers of people who move to the UK for less than a year.
Related briefings:
Official data on migration and crime is full of holes
There is much public interest in the topic of immigration and crime, and yet very little data is published, making it difficult to get a clear view of the facts.
We don’t have any official data on the nationalities or immigration statuses of people arrested as suspects, prosecuted in criminal cases, or convicted of crimes. Data on the number of prisoners in England and Wales is the only place in the regularly published justice statistics where a breakdown by nationality is recorded. These figures do not cover immigration status or duration of residence, including whether the person was a migrant in the UK as opposed to a short-term visitor.
Crime data by nationality does, in some cases, exist internally and can be retrieved from government departments and police forces by people making Freedom of Information (FOI) requests, such as arrest figures by nationality published in 2024 by the Metropolitan Police. However, there are two main problems with the data.
First, in the data itself. It is often not clear how nationality is being recorded—whether it is reported by the individual or checked against official records. Definitions may be inconsistent across datasets. Immigration status is usually absent. For example, none of the data tells us whether suspects were resident in the UK at the time of arrest as opposed to being visitors from overseas. Figures obtained through FOI will usually not have been quality-checked to the usual standard of government statistics.
Second, it is hard to interpret some of the figures without knowing how big the relevant populations are. For example, it is clear that Albanians are overrepresented in prisoner statistics, but we cannot be confident how much, without reliable figures on the number of Albanian citizens in the UK, an issue covered in section two. Slightly better data on country of birth is available (for example, from the census), but none of the justice datasets include this as a characteristic.
If immigration status, nationality or country of birth was recorded at each point in the justice system, it might be possible to carry out research to judge whether migrants are under- or over-represented in, for example, prosecution and conviction figures, and how this varies by immigration status and offence type.
The data on migrants as victims of crime is also limited to only a single, high-level estimate made using the ONS’s crime survey.
Recognising the interest in this area, the Home Office has announced improvements to its data on foreign national offenders (FNOs)—migrants convicted of crime in the UK, although it is not yet clear what will be included in future publications.
Related briefings:
Local migration figures don’t give us a clear or coherent picture
The uncertainty of migration figures is a particular problem at the local level, where estimates of population size feed into planning and resourcing decisions.
The problem for local authorities now is that it is very hard to piece together a full picture of who is moving to and from their area. The ONS does publish overall figures estimating how many people it thinks have migrated to and from local authorities. The figures rely on the same assumptions as the national level figures, making them uncertain, with additional assumptions needed to distribute that migration across local areas.
The local figures also can’t provide much detail about the characteristics of who is migrating (although there are further estimates by sex and age). Other sources can fill in parts of the picture, notably statistics on for international students (published with a long delay) and NINo registrations for nationality breakdowns by local authority.
However, local authorities struggle to get usable information on other groups, such as partners of British citizens, people on seasonal worker visas, or asylum applicants who move within the UK after receiving refugee status, higher education enrolments for international students (published with a long delay) and NINo registrations for nationality breakdowns by local authority.
It’s also possible to find out detailed information about the migrant population of small areas from the once-in-a-decade census, which captures data on country of birth, national identity, passports held, and last place of residence. The census shows the population as a snapshot at a single point in time—the last one took place in March 2021, during the pandemic (and was postponed to 2022 in Scotland, for this reason). Census data can go out of date quickly, particularly when migration levels are high.
Knowing more about the profile and demographics of migrants at the local level would help policymakers and local stakeholders to anticipate important things like how many people are likely to remain long-term and what public resource demands they may have. For example, non-EU students and their dependents added over 1 million people to the UK population between 2021 and 2024, and will have been concentrated in university towns and cities.
Producing accurate local-level data is technically challenging, but the Home Office or ONS could provide a breakdown of visas or migration to local authorities, separating out some distinct groups such as higher education students or visa holders whose addresses or places of work are available in Home Office records. The address data the Home Office holds will not always be accurate where people have moved or where employers have multiple locations, but would nonetheless provide a better picture than currently available.
Related briefings:
There is not enough information about the impact of migration on public services or on government spending
The impacts of migration on public services are difficult to measure—but the job is made even harder in the UK because of limited data.
First, a big question is what difference migrants make to the economy or, in other words, their fiscal impact. The Treasury can’t plan public spending without some idea of the impact of migration, and the Home Office needs to understand the fiscal impacts of its policies when it designs them.
Fiscal impact is not straightforward to measure because it requires looking at a lot of different data sources to work out how much migrants earn and pay in tax versus the cost of providing them with public services and any benefits. On one side of the equation—migrants’ earnings—the existing data has some gaps, such as on the earnings of the self-employed. On the other, what migrants receive—this often involves making a lot of assumptions about average use of public services and how much this translates to in terms of spending.
Recently, the government has started doing much more precise analysis of visa holders’ earnings by matching data across internal datasets, which helps fill in the picture. This has only been done so far in the form of one-off exercises, but it shows the potential. In June 2025, the Department for Work and Pensions started publishing the number of universal credit claimants by broad immigration status and nationality grouping. While this is a welcome addition to the evidence base, the data on claimants with indefinite leave to remain has known inaccuracies, which make it unreliable.
Breaking the figures down by people’s length of residence in the UK would also help to understand the impact of migration on benefits spending.
Second, some questions about immigration and the school system cannot be answered with the currently available data, including basic facts like the number and immigration status of pupils, and how many new joiners there are each year who come from overseas. We don’t have any substantial data on how migrant children fare in the classroom, and existing analysis has had to rely on a highly imperfect proxy, namely, students registered by their teachers as having English as an additional language.
Knowing information like this would help us understand the short-term impact of immigration on education in state schools.
Third, high net migration without equivalent creation of new properties should increase housing scarcity and prices, but surprisingly little hard evidence has been collected on this topic. Academic work has provided mixed findings on house prices, and this complex area of research merits more attention. To make informed policy decisions, policymakers need to know the extent to which immigration to the UK makes any difference to house prices, rents, and competition for housing, but there are no mechanisms in place to measure these impacts in an ongoing way.
Related briefings:
- The Fiscal Impact of Immigration to the UK
- Migrants and Housing in the UK
- Migration and the health and care workforce
Room for improvement
The UK already has a formidable offering of regularly published statistics relating to immigration, and we have seen a lot of improvements to it over time. The Home Office data are particularly detailed, answering many more questions than they did in the past. But as we’ve identified here, there are still major gaps that stymie public debate.
In some areas, such as criminal justice and ONS immigration and emigration statistics, work to improve the data is already underway. In other cases, such as asylum, enforcement, and human rights data, it is not clear whether there is a strategy for improving the data.
In areas such as policing, courts, and immigration enforcement, administrative data often does exist internally on issues of public interest, and a task for the departments involved in collecting this data is to make sure this is done consistently and/or that enough context is provided when the data ends up being released.
In putting together this list, it has also become clear that the government can sometimes respond relatively quickly to the need for data and analysis by combining existing data sources or doing one-off surveys. Where these methods can be extended into a longer-term way of monitoring the same issues, this could benefit future policymaking.
Many of the areas of improvement we identify in this report are relatively general. Some more specific, technical suggestions about precisely which data points could be collected or published are provided in the table below.
Table 1
| Data gap | Possible solutions |
|---|---|
| Migrants’ economic outcomes over time | • Regularly link Home Office visa records and HMRC’s Pay As You Earn (PAYE) Real Time Information (RTI) data to avoid relying on one-off matching exercises. Link data.retrospectively for at least 10 years to understand long-term outcomes for those previously granted ILR, by initial immigration route – including for humanitarian routes and the asylum system. • Link immigration records to the National Insurance number database so that current nationality and specific immigration status can be reflected in HMRC and DWP statistics. • Publish data on self-employment earning by nationality, country of birth or migration status. |
| Migrant population by immigration status | • Reinstate regular publication of estimates of the UK population by country of birth and nationality group (with confidence intervals). • Include the same level of detailed breakdown of visa/ leave categories in the Migrant Journey dataset as in the Immigration System Statistics (i.e., as in the entry clearance visa statistics and extensions datasets). • Collect data on the total number of visa holders with no recourse to public funds (NRPF) and visa holders whose NRPF condition has been lifted. • Collect data centrally on the number of refugees being assisted by local authorities due to having NRPF. |
| Asylum interactions with the rest of the immigration system | • Provide a full breakdown of year and route of entry for all nationalities (currently only the most common routes are given in table Asy_01d). • Include all asylum seekers in Migrant Journey data. • Publish data on ‘further submissions’ by refused asylum seekers for the right to remain and the outcome of these, as part of the quarterly appeals data. • Reinstate the statistics on asylum cases ‘awaiting further review’ and disaggregation of the post-decision ‘work in progress’ asylum caseload as soon as possible. • Include more categories in the breakdown of pending asylum caseload by duration (i.e. over two years). • Publish details of spending on asylum accommodation by type (including hotels) in the Home Office annual report. Publish the average cost-per-night of asylum hotels and other accommodation types quarterly in the Migration Transparency data. • Local authorities outside of England could publish data on refugees who are assisted to prevent homelessness on leaving asylum accommodation. • Provide a more detailed breakdown of the ‘asylum/ protection/ revocation of protection’ category in the Ministry of Justice’s Tribunal Statistics to make clear how many cases are appeals against first-instance refusals. |
| Lack of data on human rights claims and routes | • Separately identify ‘exceptional circumstances’ grants for entry clearance visas and in-country leave to remain. • Separately identify and publish data on grants of leave on human rights grounds, by 1) categories of human rights grants, e.g. 20-year regularisations, private life by age category; and 2) whether leave was granted following Home Office review or judicial decision. • Add the different human-rights sub-categories to Migrant Journey data and extensions data, including extensions by previous immigration category (adding a category for ‘no status’ where people are regularized). • In the Tribunal statistics, separately identify human rights and asylum cases. |
| Limits to data on enforcement and returns | • Publish data on voluntary returns by previous immigration status and duration, e.g. short-term overstayer, long-term overstayer, unauthorised entry, leave to remain revoked. • Create a ‘Migrant Journey’ style dataset on foreign national offenders leaving prison, that identifies their changes in status over time (e.g. left UK, granted legal status, in the community with restricted leave). • Include a breakdown in the return statistics by type of assisted voluntary return package (cash, in-kind assistance, etc.). • Publish spending on assisted voluntary return in the Home Office annual report. • Publish a quarterly snapshot of the number of ‘known individuals’ in Immigration Enforcement’s caseload on at least an annual basis in the Migration Transparency data. • Include a breakdown in the detention statistics showing number of previous episodes in detention for people entering detention, total time spent in detention across all episodes, and bail outcomes by whether detainees have legal representation. |
| Size of the unauthorised population | • Produce more detailed breakdowns of the known population of people liable for removal, by latest status (e.g. refused asylum, overstayed visa). • Publish data on transitions in and out of legal status, drawing on the approach used in the Home Office evaluation of the Compliant Environment. • Re-instate exit checks data publications in some form. • Work to plug the missing travel data in the Home Office’s main border control database, HOBI (i.e. failed exit-entry matches and gaps in coverage of Irish land-border crossings). |
| UK immigration and emigration | • Develop methods to measure the immigration and emigration of British nationals using administrative sources, for example using advanced passenger information (API), more detailed ‘activity’ data such as NHS records, and/or Home Office Borders and Immigration (HOBI) data. • Develop methods to understand immigration and emigration patterns of people with Indefinite Leave to Remain and visa overstayers. • Publish figures on short-term migrants (less than one year), by immigration category. |
| Insufficient crime data | • Include nationality and immigration status in published data on prosecutions, convictions, sentencing and proven reoffending. • In the Ministry of Justice’s Offender Management Statistics, provide a breakdown of offence group by nationality group, immigration status and age. • Include nationality group in the statistics on offenders on licence and home detention curfew. • Explore the feasibility of collecting country of birth in criminal justice and offender management statistics. • Provide a more detailed breakdown of foreign national offenders living in the community: e.g. by offence category, nationality, and time since becoming time-served. • Include more detail on victims of crime by country of birth, in the ONS’s analysis of its crime survey of England and Wales. |
| Local migration data | • Include local-authority level breakdowns by nationality grouping and reason for migration where available (work, study, family, humanitarian, other) in Home Office immigration statistics and ONS components of population change data. • Publish local-authority level data on non-UK citizen employees (ideally linked to immigration status) from HMRC. • Publish confidence intervals or another measure of uncertainty with the local authority-level migration flow estimates in ONS population data. |
| Impact on public services and finances | • Include an age breakdown for dependents in the entry clearance visa statistics (adult/child and, preferably a further breakdown to identify school-age children). • Explore ways of analysing the use of schools and the NHS by immigration status, while protecting the data of school children and patients. • If DWP data on universal credit claimants by nationality and immigration status could be live-linked with Home Office visas and immigration data, that would avoid the problem now of some people’s immigration status not being updated in the DWP dataset (notably, people with ILR who become British citizens). |
Acknowledgements
Thanks to Karl Williams and several anonymous reviewers for comments on earlier drafts. We are also grateful to the substantial number of migration experts who sent us their views on where the main evidence gaps lie.
