Irregular migration to the UK, year ending December 2023
Published 29 February 2024
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This publication is available at https://www.gov.uk/government/statistics/irregular-migration-to-the-uk-year-ending-december-2023/irregular-migration-to-the-uk-year-ending-december-2023
1. Introduction
This statistical release from the Home Office provides an overview of people who come to the UK irregularly. It includes those arriving on a small boat across the English Channel (a ‘small boat arrival’), along with some other groups arriving without prior lawful permission.
Some people may also enter the UK on regular routes and their status subsequently become irregular (for example, if they overstay their visa). Others may enter through an irregular method and remain undetected or will be detected some time after their arrival. Other people may enter irregularly but obtain ‘regular’ status (for example, following an application for asylum).
The statistics presented here relate to the number of people detected on, or shortly after, arrival to the UK on various irregular routes. They do not include all those who enter the UK through irregular routes, nor the number of irregular migrants currently present in the UK. It is not possible to know the exact number of people currently resident in the UK without permission, nor the total number of people who enter the UK irregularly.
Some people seek to enter the UK without valid permission but are prevented from reaching the UK border (for example, at the juxtaposed controls in France and Belgium, or further afield, if prevented from travelling). Prevented attempts are not counted in this release. Any counts of attempted entries may relate to multiple attempts by the same individual, and therefore will not relate to numbers of persons.
Additional information is provided in the ‘About the statistics’ section and in the ‘user guide’.
2. Irregular arrivals
Not all arrivals will be detected and the proportion of arrivals detected will vary by method. Therefore, it is not advisable to directly compare recorded detections on different methods of entry. However, some broad trends can be observed.
In 2023, there were 36,704 irregular arrivals, one-third (33%) fewer than in 2022, and 80% of these arrived on small boats.
In the 3 months from October to December 2023, there were 55% fewer irregular arrivals than in October to December 2022. Small boats have been the predominant recorded method of entry for irregular arrivals since 2020, when entries by this method increased rapidly and entries by other methods declined (likely in part due to the COVID-19 pandemic making other methods of entry, such as air or ferry, less viable). Small boat arrivals are also the most visible of the irregular methods of entry, so the most likely to be recorded.
Small boat arrival numbers are subject to seasonal fluctuations due to changes in the weather, with peaks in warmer summer months (quarter 3 (Q3), July to September), as seen in figure 1. Comparisons of arrivals between the same months in different years may also be affected by differences in conditions.
Figure 1: Detections at the UK border, by method of entry, January 2018 to December 2023
Source: Irregular migration to the UK - Irr_D01
2.1 Nationalities and demographics of arrivals
Since January 2018, 70% of people arriving irregularly have been adult males aged 18 and over.
There is some variation in age and sex between those arriving by the 4 different irregular methods of entry. Since 2018 adult males account for 59% of inadequately documented air arrivals, compared to 75% of small boat arrivals.
Since 2018 just under one-fifth (19%) of irregular arrivals have been children aged 17 and under. The proportion is slightly higher for detections in country (28%) and at UK ports (26%) and slightly lower for inadequately documented air arrivals (14%) and small boat arrivals (17%). There may be financial, social, physical or geographical factors which influence the method of entry individuals use and the types of individuals detected.
Around one-sixth (17%) of irregular arrivals in 2023 were Afghans.
People arriving irregularly often use a number of methods of entry and choices may relate to individual circumstances and change over time (see Irr_D01). The most commonly detected nationalities arriving in 2023 generally appeared in the top 5 for 2 or more methods of entry. This was except for Albanians, who were only in the top 5 for recorded detections at UK ports (having been common in small boats only in the summer of 2022) and Georgians, who were only in the top 5 for inadequately documented air arrivals (table 1). Afghans were in the top 5 for all 4 entry methods.
Table 1: Top nationalities arriving for each irregular method of entry, in 20231,2
| Rank | Small boat arrivals (% of total) | Inadequately documented air arrivals (% of total) | Recorded detections in the UK (% of total) | Recorded detections at UK ports (% of total) |
|---|---|---|---|---|
| 1 | Afghanistan, 5,545 (20%) | Iran, 1,114 (29%) | Iraq, 575 (18%) | Albania, 54 (16%) |
| 2 | Iran, 3,562 (13%) | Georgia, 363 (9%) | Sudan, 561 (18%) | Sudan, 36 (11%) |
| 3 | Turkey, 3,040 (11%) | Afghanistan, 324 (8%) | Iran, 433 (14%) | Afghanistan, 36 (11%) |
| 4 | Eritrea, 2,662 (9%) | Turkey, 305 (8%) | Eritrea, 335 (11%) | India, 26 (8%) |
| 5 | Iraq, 2,545 (9%) | India, 260 (7%) | Afghanistan, 277 (9%) | Iraq, 26 (8%) |
Source: Irregular migration to the UK - Irr_D01
Notes:
- The top nationalities are those with the highest number of irregular arrivals for each separate method of entry in 2023.
- Excludes small boat arrivals labelled as ‘Not currently recorded’ in the detailed and summary tables that accompany this release, for whom information on nationality is not yet available.
The proportion of small boat arrivals who were Afghans was the same in 2023 as in 2022. However, the number of Afghan small boat arrivals has decreased by 39% in 2023 (figure 2).
Albanians made up a substantial proportion of small boat arrivals between July and September 2022. However, since then the number of Albanian small boat arrivals has decreased substantially, with 924 arrivals in 2023, compared to 12,658 arrivals in 2022.
Figure 2: Top nationalities arriving on small boats, January 2021 to December 20231,2
Source: Irregular migration to the UK - Irr_D01
Notes:
- The top nationalities are those with the highest number of small boat arrivals since January 2021.
- Excludes arrivals where information on nationality was not recorded in the dataset.
3. How many people were detected arriving by small boats?
3.1. Number of people arriving by small boat
Statistics on small boats include individuals who were detected on arrival to the UK, detected in the Channel and subsequently brought to the UK, and those encountered in the UK who were suspected of having arrived on a small boat within the previous 72 hours. They do not include any persons who arrived on larger vessels (such as on a ferry), those who arrived in the UK undetected or those prevented from departing France or intercepted by French authorities and returned to France (see the ‘user guide’ for more details).
In 2023, 29,437 people arrived on small boats, 36% fewer than in 2022 (45,774).
Small boat arrivals from October to December 2023 were 64% lower than in the same 3 months of 2022. This may partly have been due to poorer weather conditions, among other factors.
The decrease in 2023 was largely due to a 93% reduction in Albanians arriving in 2023 (as noted above in section 2.1). The number of small boat arrivals from other nationalities decreased 14% overall in 2023.
Figure 3: Cumulative number of people arriving by small boats each month, January 2021 to December 2023
Source: Irregular migration to the UK summary tables - Irr_02a
3.2. Number of boats and people per boat
The average number of people per boat increased to 49 people per boat in 2023, compared with an average of 41 people per boat in 2022.
Figure 4: Number of small boats arriving and average number of people per boat, January 2018 to December 2023
Source: Irregular migration to the UK summary tables - Irr_02a
In 2023, 602 small boats arrived without permission, 46% fewer than the 1,110 in 2022. Although the number of people and boats arriving have decreased, the average number of people per boat has continued to increase (figure 4). The average number of people per boat was 49 in 2023, compared to only 13 in 2020 and only 7 per boat in 2018.
In 2023, there was at least one small boat recorded arriving on 2 out of every 5 days (an arrival on 140 of the 365 days). This was a slightly lower rate compared with 2022 (162 of the 365 days) but slightly higher than the rate of just over a third of days in 2020 (130 of the 366 days).
4. Asylum claims from small boat arrivals
Due to the transition to a new data system, data for asylum claims from small boat arrivals for June to December 2023 was unavailable at the time of publication. Further updates will be included in future editions of this publication once available. Therefore, data for the ‘year ending June 2023’ reports on the period July 2022 to May 2023.
The majority of small boat arrivals claim asylum and small boat arrivals accounted for over one-third (37%) of the total number of people claiming asylum in the UK in the year ending June 2023.
In the 11 months to end of May 2023, 90% of small boat arrivals had an asylum claim recorded either as a main applicant or dependant.
More detail on asylum claims from small boat arrivals is available in section 4 of the ‘Irregular migration to the UK, year ending June 2023’ release.
For more details on people applying for asylum, see the ‘How many people do we grant protection to?’ chapter of the Immigration System Statistics quarterly release.
5. Potential victims of modern slavery
Modern slavery includes any form of human trafficking, slavery, servitude or forced labour. Potential victims of modern slavery in the UK are referred to the National Referral Mechanism (NRM). Statistics on modern slavery referrals show the overall number of NRM referrals has been increasing. For more information on NRM referrals, see the ‘user guide’.
Due to the transition to a new data system, data for small boat arrivals with National Referral Mechanism (NRM) referrals from June to December 2023 was unavailable at the time of publication. Further updates will be included in future editions of this publication once available. The section below refers to the latest available data up to the end of May 2023.
5.1 Small boat arrivals with modern slavery referrals
A small proportion of small boat arrivals are referred to the NRM as potential victims of modern slavery. Of the 91,918 small boat arrivals since 2018, fewer than one in 10 (9% or 7,923 people) had been referred to the NRM. Most of these individuals (7,466 or 94%) also had an asylum claim lodged.
The number of small boat arrivals in each year with NRM referrals is likely to increase, particularly for more recent years, as people have more time to identify as a potential victim and be referred into the NRM.
5.2 Outcomes of small boat modern slavery referrals
Individuals referred to the NRM receive decisions on 2 grounds: reasonable grounds, and conclusive grounds.
A positive reasonable grounds decision means the decision-maker believes, based on objective factors but falling short of conclusive proof, that a person may be a victim of modern slavery (human trafficking or slavery, servitude, or forced or compulsory labour).
Following a positive reasonable grounds decision, a conclusive grounds decision will be made. A positive conclusive grounds decision indicates that, on the balance of probabilities, there is sufficient information to consider the individual is a victim of modern slavery.
Most small boat arrivals with NRM referrals have received a reasonable grounds decision, but not yet received a conclusive grounds decision. This is because most reasonable grounds decisions are issued within 5 days of the referral, but conclusive grounds decisions can take considerably longer. More recent periods will naturally have a higher proportion awaiting a conclusive grounds decision, as less time has passed to allow for a decision to be made.
More than three-quarters (78%) of reasonable grounds decisions for small boat arrivals since 2018 have been positive. Of the 780 conclusive grounds decisions issued, again over three-quarters (78%) were positive.
More detail on small boat arrivals with NRM referrals is available in section 5 of the ‘Irregular migration to the UK, year ending June 2023’ release.
6. Returns of small boat arrivals
The data presented below shows the number of enforced and voluntary returns of small boat arrivals. Returns figures, especially voluntary returns, may be revised upwards as it can take time for the Home Office to become aware of such departures and for them to be recorded on the system.
Between 2018 and 2023, there have been 2,580 returns of small boat arrivals, or 2% of all small boat arrivals, 1,889 of these returns occurred in 2023.
Figure 5: Returns of small boat arrivals, January 2018 to December 2023
Source: Irregular migration to the UK summary tables - Irr_02e
For more information on returns, see the ‘How many people are detained or returned?’ chapter of the Immigration system statistics quarterly release.
7. About the statistics
The underlying casework systems on which this data is based are undergoing a process of change and therefore the published numbers may change in future quarters.
These statistics should not be used to infer the size of the irregular population in the UK, nor the total number of people entering the UK irregularly. For a number of reasons, it is not possible to know the exact size of the irregular population, or the number entering irregularly, and so we have not produced any official estimates for this number.
This is because:
- some people will successfully evade border controls and remain in the UK undetected
- some people may enter the UK on regular routes and their status subsequently become ‘irregular’ – for example, if they overstay a visa (it should be noted that there are a number of ways in which a person’s departure from the UK may legitimately not be recorded on the system)
- the data sources available count the number of recorded detections - in some instances the same person may be detected multiple times, either on the same route or across different routes (such individuals will be counted multiple times in the statistics)
- some people may enter the UK irregularly but obtain ‘regular’ status – for example, following a successful asylum application
Figures on detections may be affected by the levels of operational activity at the border and overseas, so should not be used to infer levels of irregular migration. Changes in detection could be a result of changes in operational activity as well as changes in the number of people attempting to enter the UK irregularly and recording practices.
Data on detections includes the number of people recorded as attempting to enter the UK, having been detected on, or within 72 hours of arrival to the UK. It does not include those prevented from reaching the UK border (for example, those prevented from boarding transportation at their port of embarkation or where their concealment in a vehicle has been detected prior to arrival in the UK).
For more information on the data in this release, please see the ‘user guide’.
8. Data tables
Data referred to here can be found in the following tables: