Almost 300 people have been arrested in a "week-long crackdown" on asylum seekers illegally working for delivery app firms.
Officers targeting suspected illegal workers in Hillingdon, the borough with highest concentration of migrant hotels in London, as well as Dumfries in Scotland and Birmingham stopped 1,780 people.
During Operation Equalize in West London, officers arrested seven Indian nationals, the Home Office said. Five were detained because of the action on Tuesday, July 22.
Across the country some 280 people were arrested, with 53 now having their asylum support reviewed. The Government said this could result in their support being suspended or withdrawn.
The Home Office described the operation as a "nationwide intensification week" targeting illegal working hotspots, with a focus on the gig economy and people working as delivery riders.
It comes after claims in June that there was “clear evidence” of migrants working illegally for the food delivery firms while living in asylum hotels in London.
Immigration enforcement teams are set to receive £5million from the £100million in funding already announced for border security, aimed at increasing visits by officers in these areas over the coming months, the Home Office said.
Border security minister Dame Angela Eagle said: "Illegal working undermines our border security and we're cracking down hard on it.
"That's why we have intensified our enforcement activity right across the UK to crack down on those who think they can evade immigration and employment laws in the UK. "
As well as the arrests, 51 businesses including car washes and restaurants were issued with penalty notices that could see them handed hefty fines of up to £60,000 per worker if they are found to have employed someone without the right to work in Britain.
Eddy Montgomery, enforcement director at the Home Office, said officers were taking action "around the clock" against "those who think they can get away with working illegally".
He added: “I welcome the additional funding which will allow us to strengthen our enforcement efforts against illegal working further, to ensure those fuelling it are caught.”
Asylum seekers in the UK are normally barred from working while their claim is being processed, though permission can be applied for after a year of waiting.
Officials had indicated there would be an increase in work to target areas of suspected activity, as ministers hope to tackle the "pull factors" attracting migrants to the UK.
It comes after the Government announced it would share information about asylum hotel locations with food delivery firms, such as Deliveroo, Just Eat and Uber Eats, in a bid to disrupt hotspots.
The gig economy firms have also said they will ramp up facial verification and fraud checks over the coming months to prevent people working as riders without permission.
The operation was also supported by police forces across the UK, with officers seizing 71 vehicles throughout the week, including 58 e-bikes, as well as £8,000 in cash under the Proceeds of Crime Act. Around £460,000 in suspected illegal cigarettes were also seized.
