Three people have been arrested for working illegally at a pub popular with celebrities including Kate Moss and Pete Doherty.
Two Mongolian men and an American woman were held at the Hawley Arms in Camden, north London, on Saturday, the UK Border Agency (UKBA) said.
The Hawley Arms is working 'closely' with the UKBA over the issue
The pub was a favourite of the late singer Amy Winehouse, and has included model Kate Moss, singer Pete Doherty and designer Sadie Frost among its customers.
It also hit the headlines in 2008 when the building was ravaged by fire and had to close for eight months for repairs.
UKBA officers held a 25-year-old woman who was found to be working in breach of her visa conditions, while one of the men, 35, had entered the UK illegally. The second man, 28, had overstayed his visa.
All three are being held pending deportation from the UK.
The business was warned that it could face a fine of up to £10,000 per illegal worker unless it can prove that the correct checks were carried out.
Steve Fisher from UKBA said: "This is the latest in a series of raids we have carried out in north London and more are planned in the future. For those who are living and working in the country illegally there is no hiding place.
"We are also targeting employers who fail to carry out the correct checks on their staff.
"My officers are happy to work with employers to help them make sure they know what needs to be done, but those who flout the rules could face big fines."
Ruth Mottram from the Hawley Arms said: "We take our responsibilities as an employer very seriously and believed the staff in question to have valid UK visas. We are therefore very concerned that this problem has arisen and are working closely with the UK border agency in support of their investigation."