The government said arrests by immigration enforcement teams had risen in every region of the UK, with the largest number of arrests in London, the West Midlands and south-west England.
In London, more than 2,100 arrests were made last year, a 47% rise compared to 2024.
Meanwhile, more than 1,100 arrests were made in both the West Midlands and south-west England, a rise of 76% and 91% respectively.
In Wales, 1,320 raids were carried out last year, resulting in 649 arrests – a rise of 103% and 85% respectively.
In Scotland there were 695 raids leading to 400 arrests – a rise of 61% and 49% respectively.
In Northern Ireland, 187 raids led to 234 arrests – a rise of 76% and 169% respectively.
Among the businesses raided were a warehouse in Shoreham-by-Sea, West Sussex, on 25 November, where 13 people were arrested, with 11 Brazilian and Romanian nationals detained for removal from the UK.
Other examples included a raid on a construction site in Swindon on 16 December, which led to 30 arrests of Indian and Albanian men, who were nearly all detained for removal.
Meanwhile, a raid on a market at Kempton Park racecourse in Surrey on 11 December resulted in 11 arrests.
Home Secretary Shabana Mahmood said: “There is no place for illegal working in our communities.
“That is why we have surged enforcement activity to the highest level in British history so illegal migrants in the black economy have nowhere to hide.
“I will stop at nothing to restore order and control to our borders.”
The surge in raids followed an extra £5m of funding for Immigration Enforcement last year.
The government is also planning to introduce digital ID, which will be mandatory to prove someone’s right to work by 2029, to make it harder for migrants to work illegally.