How many people come to the UK irregularly?
Published 22 May 2025
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This publication is available at https://www.gov.uk/government/statistics/immigration-system-statistics-year-ending-march-2025/how-many-people-come-to-the-uk-irregularly
Back to ‘Immigration system statistics, year ending March 2025’ content page.
Data relates to the year ending March 2025 and all comparisons are with the year ending March 2024 (unless indicated otherwise).
Additional information is provided in the ‘About the statistics’ section and in the user guide.
1. Irregular arrivals
Not all irregular 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.
There was an increase in the number of irregular arrivals in the latest year, due to an increase in small boat arrivals.
In the year ending March 2025, there were 44,125 detected irregular arrivals, 14% more than in the previous year, and 86% of these arrived on small boats. Small boats have been the predominant recorded entry method for irregular arrivals since 2020, when detections on this method increased rapidly and detections on 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, and have remained high even as other routes have become more viable again.
Small boat arrival numbers fluctuate from day to day, often due to changes in the weather, with peaks in warmer summer months when crossing conditions are more favourable. Comparisons of arrivals between months or years may also be affected by differences in weather conditions. As a result, we do not advise making comparisons between shorter periods.
Apart from small boats, other irregular arrivals comprised: inadequately documented air arrivals (7%), recorded detections in the UK within 72 hours of arrival (6%), and recorded detections at UK ports (1%).
The number of inadequately documented air arrivals has been between 3,200 and 5,300 each year since 2018, except for 2020 and 2021 when numbers were lower due to COVID-19 travel restrictions. There were 2,585 recorded detections in the UK in year ending March 2025, more than two-thirds (69%) fewer than the recent peak of 8,239 in 2019.
Similarly, the number of recorded detections at UK ports in the year ending March 2025 (277) has decreased by nearly three-quarters (74%) since 2018. The most common nationality in this category were Albanians (66 detections) (see Section 1.1).
Figure 1: Detections of irregular arrivals to the UK, by method of entry, January 2018 to March 2025
Source: Irregular migration to the UK detailed dataset, year ending March 2025 - Irr_D01
1.1. Nationalities and demographics of arrivals
Since 2018, over two-thirds of people detected arriving irregularly have been adult males aged 18 and over.
Since January 2018, 71% of people detected arriving irregularly have been adult males aged 18 and over. Just under one-fifth (18%) of detected irregular arrivals have been children aged 17 and under.
Almost three-fifths (57%) of detected irregular arrivals to the UK in the year ending March 2025 were from 5 nationalities (Afghans, Iranians, Syrians, Eritreans, and Sudanese).
The most common nationality detected irregularly arriving in the latest year were Afghans (6,051 irregular arrivals), of whom 95% arrived on small boats (see Section 2.3 for more detail on small boat arrivals by nationality).
Iranian, Syrian, Eritrean, and Sudanese nationals were in the top 5 most common nationalities detected arriving in the UK for multiple irregular methods of entry. Iranians were the most common nationality arriving inadequately documented by air (734 arrivals) and Sudanese nationals the most common nationality detected in the UK (548 detections).
For most of the nationalities in Table 1, their most common irregular method of entry was on small boats, reflecting the dominance of that method as a route for irregular entry (see Section 2.3). However, for Georgian, Chinese and Stateless nationals, their most common irregular method of entry was by air.
Financial, social, physical and geographical factors may influence the method of entry individuals use and the types of individuals detected arriving. These factors may also change over time.
Table 1: Top 5 most common nationalities detected arriving by each irregular method of entry, in the year ending March 20251,2,3
| 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) | |
|---|---|---|---|---|
| Afghanistan, 16% |
Iran, 23% |
Sudan, 21% |
Albania, 24% |
|
| Syria, 12% |
Georgia, 12% |
Iran, 14% |
India, 13% |
|
| Eritrea, 12% |
Stateless, 10% |
Iraq, 12% |
Pakistan, 12% |
|
| Iran, 11% |
Sri Lanka, 10% |
Eritrea, 11% |
Sudan, 10% |
|
| Sudan, 9% |
China, 5% |
Syria, 7% |
Turkey, 9% |
|
| Total | 36,529 | 3,240 | 2,585 | 277 |
Source: Irregular migration to the UK detailed dataset, year ending March 2025 - Irr_D01
Notes:
- The top nationalities are those with the highest number of detected irregular arrivals for each separate method of entry in the year ending March 2025.
- Excludes small boat arrivals labelled as ‘Not currently recorded’, for whom information on nationality is not yet available.
- The nationality recorded as stateless includes those officially recognised as stateless, including those recognised as Kuwaiti Bidoon.
2. Small boat arrivals
2.1. Number of small boat arrivals
Statistics on small boat arrivals 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 people who arrived on larger vessels (such as 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’).
The number of people who arrived in the UK on small boats has increased by over one-fifth compared with the previous year, although still 17% fewer than the peak year of 2022.
In the year ending March 2025, 38,023 people arrived in the UK on small boats, 22% more than in the previous year (31,079). Small boat arrivals were relatively low from 2018 to 2020, with 10,608 small boat arrivals in total across these 3 years. However, since 2021 there have been between 29,000 and 46,000 small boat arrivals each year, with the highest number of arrivals in 2022 (45,774).
Figure 2: Cumulative number of people arriving by small boats each month, January 2020 to March 2025
Source: Irregular migration to the UK summary tables, year ending March 2025 - Irr_02a
2.2. Number of boats and people per boat
The average number of people per boat has increased year on year since 2018.
Figure 3: Number of small boats arriving and average number of people per boat, January 2018 to March 2025
Source: Irregular migration to the UK summary tables, year ending March 2025 - Irr_02a
The average number of people per small boat has increased each year, rising to 54 people per boat in the year ending March 2025 compared with 50 people per boat in the previous year. In the year ending March 2025, 700 small boats arrived in the UK without permission, over one-third (37%) fewer than the highest number of small boats recorded in the year ending March 2022. However, an increase in the average number of people per boat (54 compared to 29 in the same period ending March 2022), resulted in a 20% higher number of people recorded as small boat arrivals.
2.3. Nationalities of small boat arrivals
The top 5 most common nationalities (Afghan, Syrian, Eritrean, Iranian, and Sudanese) arriving on small boats in the year ending March 2025 accounted for almost three-fifths of all small boat arrivals.
Afghans were the most common nationality arriving by small boat in the year ending March 2025, with Afghan arrivals at similar levels to the previous year (2% higher at 5,766 arrivals). Numbers remained lower than the peak of 9,088 Afghan arrivals in 2022 (Figure 4).
Syrian nationals were the second highest nationality and accounted for 12% of small boat arrivals in the year ending March 2025, with a total of 4,368 people. However, between January and March 2025 Syrian arrivals constituted 5% (299 arrivals) of all small boat arrivals, decreasing from 15% (1,735) between October and December 2024. This follows the fall of the Assad regime in December 2024.
Eritrea was the third highest nationality arriving by small boat in the year ending March 2025, with 4,229 arrivals, an increase of 47% on the previous year. In the most recent quarter, Eritrean nationals were the most common nationality arriving by this method accounting for 20% (1,291) of small boat arrivals.
Vietnamese nationals were the most common nationality detected arriving by small boat in the first half (January to June) of 2024, accounting for 17% of small boat arrivals. However, the number of Vietnamese small boat arrivals has since decreased. In April 2024, the UK signed an agreement with Vietnam to increase cooperation on dealing with irregular migration and the government are continuing to work with Vietnam.
Albanians were the top nationality detected arriving by small boat in 2022, with 12,658 arrivals, but have declined to only 626 small boat arrivals in the year ending March 2025.
Figure 4: Most common nationalities arriving on small boats, year ending March 2019 to year ending March 20251,2
Source: Irregular migration to the UK detailed dataset, year ending March 2025 - Irr_D01
Notes:
- The 5 most common nationalities of small boat arrivals in the year ending March 2025 plus Albania. Albania has been presented to reflect that it was a nationality with a large number of small boat arrivals over recent years but is no longer a top 5 nationality.
- Excludes arrivals where information on nationality was not recorded in the dataset.
For information on National Referral Mechanism (NRM) referrals from small boat arrivals and outcomes of NRM referrals, see irregular migration detailed datasets. For information on returns of small boat arrivals (and all returns from the UK), see the ‘How many people are returned from the UK?’ chapter of the Immigration system statistics quarterly release.
3. Asylum claims from small boat arrivals
The vast majority of small boat arrivals claimed asylum, but small boat arrivals only accounted for one-third of the total number of people claiming asylum in the UK in the year ending March 2025.
Since 2018, 94% of the people arriving in the UK on a small boat have claimed asylum. Of the 145,834 small boat arrivals claiming asylum since 2018, around three-fifths (59% or 86,646) had received a substantive decision (as of 02 April 2025, when the data used in this release was taken). Of these, 56,605 had been granted asylum or some other protection status, and 30,041 were refused.
A further 19,696 people had their claims withdrawn before an initial decision (either by the claimant, or by the Home Office). Such claims are not normally included in grant rate calculations as they are not substantive decisions on the claim itself. However, if we include withdrawals, then 53% of the total number of small boat asylum claims that have been resolved resulted in a grant of asylum or some other protection status.
The number of small boat arrivals with an initial decision on their asylum claim will change as more individuals have their claims processed. Cases where the person claiming asylum arrived irregularly since 7 March 2023 previously fell under the criteria set out in the Illegal Migration Act, which meant they could not have their asylum claims considered. However, on 22 July 2024, the Home Secretary changed the law to remove the retrospective application of the Illegal Migration Act. Consequently, decision making on claims from individuals who arrived in the UK after 7 March 2023 has resumed.
Table 2: Small boat arrivals claiming asylum and initial decision outcomes on their claims, by arrival date, January 2018 to March 20251,2,3,4,5
| January 2018 to March 2025 (people) | January 2018 to March 2025 (cases) | |
|---|---|---|
| Small boat arrivals | 154,354 | Not applicable |
| Asylum claims | 145,834 | 132,128 |
| Awaiting a decision | 29,373 | 26,499 |
| Received an initial decision (% of claims) | 86,646 (59%) |
77,374 (59%) |
| of which: | ||
| granted refugee status or other leave (grant rate) |
56,605 | 51,361 (66%) |
| refused | 30,041 | 26,013 |
| Withdrawn | 19,696 | 18,934 |
| Received an administrative outcome | 10,119 | 9,321 |
Source: Irregular migration to the UK detailed dataset, year ending March 2025 - Irr_D02 and Irr_D03
Notes:
- People includes main applicants and dependants, whereas cases include main applicants only.
- The time periods relate to the date of the small boat arrival, not the date of the asylum claim or outcome.
- Claims granted include grants of refugee status, humanitarian protection and other forms of leave.
- Grant rate is the percentage of claims that resulted in a grant of protection or some form of leave at initial decision, excluding withdrawn claims and claims which received an administrative outcome.
- There may be a small number of arrivals who claimed asylum but are not included in these figures as their small boat arrival and asylum records could not be matched properly, for example small boat arrivals for whom more detailed information is not currently recorded.
More detail on all asylum claims is available in the ‘How many people claim asylum in the UK?’ chapter and more detail on the outcomes of asylum claims is available in the ‘How many people are granted asylum in the UK?’ chapter of the Immigration system statistics quarterly release, including definitions on asylum case outcome types in the asylum detailed datasets.
4. About the statistics
The Irregular Migration statistics were designated as ‘Official Statistics’ from February 2022. For more information, please see Section 11.5 of the Immigration system statistics user guide.
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.
All statistics in this chapter relate to 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.
The statistics presented here relate to the number of people detected on, or shortly after, arrival to the UK through various irregular methods of entry. They do not include all those who enter the UK through irregular methods, 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, 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 becomes ‘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 for the same method of entry or across different methods of entry (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 claim
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.
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 reported in this chapter. However, a weekly summary of small boat arrivals and preventions is published separately, including definitions of what these figures include. This data on small boat preventions can be used to provide more context on people attempting to cross the English Channel in small boats. Any counts of arrivals and attempted entries may relate to multiple arrivals or attempts by the same individual, and therefore will not relate to numbers of people.
Publication of the number of NRM referrals from small boat arrivals and outcomes of the NRM referrals in data tables Irr_D04 and Irr_D05 have moved from a quarterly to annual update. The last quarterly release was published on 27 February 2025, with data to the end of December 2024.
For more information on the data in this chapter, please see the ‘user guide’.
5. Data tables
Data referred to here can be found in the following tables:
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