Intelligence-led immigrant raids were carried out last Thursday at The Nail Bar in Sherrard Street, Melton Kebab House in Windsor Street and USA Chicken in Leicester Street.

An agency spokesman said two immigration offenders were encountered at The Nail Bar - a 27-year-old Malaysian woman who had overstayed her visa and a 26-year-old woman whose nationality is still to be determined.

Two immigration offenders, both Turkish men and failed asylum seekers, were encountered at Melton Kebab House. One was aged 31 and the other 34.

Both businesses now face potential fines of up to £20,000 - £10,000 per illegal worker - unless they can prove that the correct pre-employment checks were carried out.

Another immigration offender, a 26-year-old Iraqi man, was encountered at USA Chicken.

He had entered the UK illegally.

The business faces a potential fine of £10,000 unless it can prove the correct pre-employment checks were carried out.

It's understood the three businesses visited by the UK Border Agency officials were given 28 days to provide the required evidence.

Gail Adams, UK Border Agency regional director, said: "We are working hard to pull the plug on the illegal jobs which lure illegal immigrants to come to the UK in the first place.

"Illegal working is unfair on honest employers who recruit staff with the right to work in the UK and who pay them a proper salary.

"Employers who don't play by the rules will get struck off our register, lose the right to recruit staff from outside Europe, face on the spot fines and could potentially end up in jail."

Guidance for employers on preventing illegal working can be found on the UK Border Agency website, www.ukba.homeoffice.gov.uk/employingmigrantsor by calling the UK Border Agency employer's helpline on 0845 010 6677.

• Anyone who suspects illegal workers are being employed can call Crimestoppers on 0800 555 111.