Question to the Home Office:

To ask the Secretary of State for the Home Department, what estimate she has made of the volume of illegal immigration since December 2021.

The Home Office publishes data on the number of people recorded being detected on, or shortly after, arrival to the UK on various routes in the Irregular Migration to the UK quarterly report. The latest data on selected methods of entry are published in table Irr_01 of the Irregular migration to the UK data tables. The latest data go up to the end of June 2022.

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 irregular migrants will successfully evade border controls and remain in the UK undetected
• some migrants who enter the UK regularly may subsequently become ‘irregular’ migrants – for example if they overstay a visa (it should be noted that there are a number of ways in which a migrant’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 migrants who enter the UK irregularly may subsequently become ‘regular’ migrants – for example, following a successful asylum application

Figures on detections may be impacted 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.