The stark figures come as Channel crossings continue at pace, with more than 40,000 migrants crossing this year alone. Nearly all claim asylum on arrival in the UK.

More than 110,000 people claimed asylum in Britain in 2024, which Migration Watch said placed growing pressure on local authorities and public services.

The group also highlighted the low rate of removals, noting that just 3 per cent of small boat migrants are returned to their home countries, while fewer than 200 have been sent back to France under the Government’s controversial “one in, one out” arrangement.

Migration Watch said the cost of small boat arrivals comes on top of other significant immigration-related expenses identified by the MAC.

The committee has also estimated that foreign spousal visas issued in a single year, 2022-23, will cost the taxpayer a net £5.6 billion over migrants’ lifetimes.

Alp Mehmet, chairman of Migration Watch, said: “Migration Watch has repeatedly warned over many years that, overall, immigration is a massive cost to the taxpayer. Ultimately, it makes us all poorer. It’s time our politicians came to their senses.”

The Migration Advisory Committee has previously warned that asylum and refugee routes carry an “unambiguously negative” lifetime fiscal impact.

In its latest report, the MAC said this is driven by lower employment rates, lower wages and higher levels of economic inactivity, alongside access to public services and long-term welfare costs.

Research cited by the committee suggests asylum seekers in comparable countries impose lifetime net fiscal costs running into hundreds of thousands of pounds per person.

The MAC has also highlighted the additional expense of housing asylum seekers in dedicated accommodation, further increasing the burden on the public purse.

The warning from Migration Watch comes amid growing concern over the sustainability of Britain’s asylum system and the long-term impact of high migration levels on public finances.

The Home Office was approached for comment.