The Home Office has kicked off a summer crackdown on illegal working in the food industry with a raid at a Tesco supplier in London.

The UK Borders Agency, part of the Home Office, will visit 100 businesses a month in London alone as the new government looks to send out a zero-tolerance message on illegal labour.

Acting on a tip-off, immigration officers accompanied by The Grocer last week arrested eight people in co-ordinated raids at Indian food supplier Chhappan Bhog. Four suspected illegal workers were arrested at its food processing site in Southall, west London, with four more ­arrested at the company's two grocery stores in Southall and Kingsbury. They are being held in immigration detention centres and could be deported "within days or weeks", UKBA said. Another two face possible deportation after they were arrested working at rented stalls outside the shops.

Chhappan Bhog, which supplies Tesco and the foodservice sector, could be fined up to £80,000 £10,000 per illegal worker if it cannot prove it carried out the required right-to-work checks. It is already paying a £20,000 fine over four illegal workers found during a raid last year.

"Britain has got a reputation around the world as a place where it's easy to work illegally and I'm very keen to change that," immigration minister Damian Green told The Grocer. "Food is a sector that does seem to suffer from illegal working."

Green called on supermarkets to back the drive. "They are hugely important in this. If it becomes known that supermarkets will not tolerate anyone that knowingly employs illegal workers, that will help in driving out illegal working."

Solicitors for Chhappan Bhog said: "Chhappan Bhog denies employing ­illegal workers and is liaising with the Home Office regarding its investigation.

"The company takes this matter very seriously but is unable to comment further while the investigation is ongoing."

Tesco declined to comment.