Migration and the asylum system statistics

Summary

There are two main sources of official statistics for migration:

The Office for National Statistics’ (ONS) Long-term international migration statistics  estimate the number of people entering and leaving the UK for 12 months or more. These statistics are published every six months with a five-month lag. They coincide with the publication of the Home Office’s immigration system statistics and National Insurance Numbers allocated to adult overseas nationals entering the UK.

The ONS is currently going through a transformation programme for international migration statistics as it moves away from survey-based estimates to admin data sources. As the transformation is ongoing, there are limited granular breakdowns available for users. These statistics often receive a lot of media coverage around the time of their publication.

The Home Office’s Migration Statistics Collection brings together all published Home Office migration data and analysis. Examples of these statistics include the number of small boats, undecided applications, refusals, returns, age disputes, settlement schemes.

Things to consider in statements about migration and the asylum system

As statistics on migration and the asylum system cover a range of complex issues, it is important to understand the specific definitions, strengths and limitations of the individual statistics output to ensure that these statistics are not used to make claims that the data cannot support.

Migration and asylum are different. The Home Office defines asylum as a status granted to applicants that recognises they have a well-founded fear of persecution in their country of origin or country of former habitual residence for reasons of race, religion, nationality, political opinion or membership in a particular social group. Migration, however, could be used to discuss any entry or exit to and from the country, including through regular visa schemes as well as settlement schemes, small boats crossings, migration of those with indefinite leave to remain and some illegal migration. The majority of long-term migrants arrive through the regular immigration system on an approved visa.

Due to its operational role in monitoring those who enter and exit the country, the Home Office holds a wealth of management information alongside the official statistics it produces. Occasionally, this management information is used in public statements. The Home Office has taken a variety of steps to publish this information where it is used to support understanding – for example, on the Illegal Migration Bill.

What to look out for when hearing statements relating to migration or asylum

It is important that users of migration statistics fully understand the terminology around the statistics and are clear when communicating this to others. Migration is the movement of people from one place to another and covers a wide range of people who are moving for different reasons. Immigration refers to people coming into the UK and emigration is people leaving the UK. Net migration is immigration less emigration. It is important when using migration statistics that users are clear on which groups of migrants they are referring to as different types of migration may have different drivers, trends and different interactions with services. For example, a person that comes to the UK to study will likely have different interactions to a person that is granted asylum in the UK.

In June 2022, the Home Office introduced a new “legacy and flow” model. Any asylum case opened after 28 June 2022, or new arrivals from this date are considered as “flow” cases and processed in line with the Nationality and Borders Act 2022. “Legacy” cases refer to cases opened before 28 June 2022. Claims around the backlog being cleared should be clear on what backlog they refer to and how cleared is being defined.

Claims should be clear on whether figures quoted refer to resettlement or asylum (or the combined total) or some other form of protection, and that the figure quoted is appropriate for the use being made of it.

An asylum application is described as a ‘non-substantiated withdrawal’ if the applicant fails to cooperate with the process to examine and decide the asylum claim within a reasonable time period. Those who are missing would fall within this group. By contrast, where the applicant actively chooses to withdraw the application, this is classified as ‘other withdrawals’. Therefore, the total number of withdrawals does not equate to the total number of asylum seekers who are missing.

Wider support

Other than the official statistics and ad hoc publication that have been highlighted there are a number of organisations that produce research and analysis on migration.

• The Migration Observatory informs and debates on international migration and public policy. You can find briefing and commentary on topics such as the impact of migration on the UK population growth and the UK’s asylum backlog.
• The House of Commons Library includes a section on immigration where you can find research briefings on changes to legal migration rules for family and work visas in 2024 and the UK-Rwanda migration and economic development partnership.
• The Institute for Public Policy Research has a migration policy unit that works with organisations in the migrants’ rights sector to provide policy analysis and advise on issues relating to immigration and integration.
• The Centre for Reseach and Analysis for Migration is an economics research centre with a focus on migration and labour economics.
• Full Fact, a team of independent fact checkers and campaigners, have also written an explainer on the UK asylum backlog.

The Home Office publishes a user guide to immigration system statistics designed to be a useful reference document on the issues and classifications that are used in the production and presentation of the Home Office Immigration system statistics releases. The Office for National Statistics has also published a technical user guide, which provides more information on how they produce the official migration statistics.

You can read more about our work on ONS transformation of Long-Term International Migration Estimates and our previous statements concerning refugees and economic migrants.