Most Britons vastly overestimate the number of irregular migrants, new research shows

A new report published today (11 December), by researchers at the University of Birmingham, reveals widespread misconceptions among the UK public about irregular migration, which includes all unauthorised methods of entering a country or overstaying a visa.

The report highlights how political narratives and media coverage shape public attitudes far more than actual evidence, such as a high levels of awareness of small boat crossings which have dominated headlines and political speeches in recent years.

Public Understanding and Attitudes to Irregular Migration in the UK, draws on a nationally representative survey of 1,147 UK adults conducted in February 2025. The report offers the first comprehensive picture of what the UK public knows about irregular migration, how they define it, and how they view irregular migrants in the context of work and integration.

Professor Nando Sigona, Chair of International Migration and Forced Displacement at the University of Birmingham, and co-author of the report, said: “At a time when irregular migration - most commonly referred to as illegal migration - is central to the political and societal debate in the UK, it is vital that we know how much the public accurately understands about the topic. Our research shows that public knowledge has sizeable gaps, but that public attitudes in the UK are far more nuanced than the current political rhetoric suggests.”

Confusion beyond small boats

One of the report’s key findings is that the UK public overestimates the scale of irregular migration. While current estimates place irregular migrants at 594,000-745,000, around 10-13% of the foreign-born population in the UK, most respondents estimated the figure at more than 10% above this.

Older respondents and those who vote Conservative or Reform UK were the most likely to overestimate, whilst younger respondents and those who vote Labour or Liberal Democrat were more likely to underestimate.

The researchers also found that:

• Irregularity is strongly associated with border crossings and asylum claims, even though many irregular migrants lose status through everyday administrative or employment-related routes.
• 3% of respondents believed incorrectly that waiting for an asylum decision led to irregular status.
• 1% recognised that overstaying a student visa as a route to irregularity, even though this is one of the main pathways into irregular status in the UK.
• 5% of people saw EU workers between contracts as potentially irregular, despite rising enforcement against EU nationals in recent years.

People who took part in research said that they favoured migrants with longer UK residence, strong recommendations, and family ties in the UK, even when they are aware of their irregular status.

However, when it came to hiring migrants, preferences were shaped by racial stereotypes. When asked to pick between two migrants from different ethnic backgrounds to hire to care for a relative, candidates from African and South Asian countries were consistently less favoured than those from European countries.

The researchers argue that this lack of understanding and more negative views of certain groups of migrants over others, is shaped by prevalent media and political narratives. Themes or topics covered by politicians and news outlets on the left and right, were the most common to come up in survey answers, whereas those that are not frequently covered had less accurate responses.

Dr Laurence Lessard-Phillips, Senior Research Fellow at the University of Birmingham and lead author of the report, said: “Our findings show that people in the UK are not necessarily hostile to irregular migration, but they are navigating a narrative environment where irregularity is equated with borders and boats. This framing obscures the more routine, legal and bureaucratic ways people lose status; shaping public understanding far more than actual evidence does.”

The report also found high levels of pragmatism and openness. Respondents were more positive toward irregular migrants who showed markers of belonging, and social distance was lowest in everyday encounters such as shops or workplaces. Markers of integration, especially English fluency and social ties in the UK, were found to strongly influence perceptions of belonging irrespective of whether a migrant was in the UK legally or not.

Professor Nando Sigona said: “Public debate is shaped by narratives, not facts. If policymakers want to foster informed debate, they must address the wider ecosystem of narratives that distort public understanding. Correcting numbers is not enough; what matters is challenging the stories that define who is seen as ‘deserving’ or ‘undeserving’.”

The report is part of the I-CLAIM project, funded by Horizon Europe and UKRI.