Police officers were joined by about 12 immigration officials from across the south-east in the "intelligence-led" operation at the Gourmet Plaza, in Cowgate.

The raid was organised and carried out by the Border and Immigration Agency's Enforcement Unit, based in St Ives.

Five unmarked people carriers swooped on the restaurant just after 6pm yesterday as diners were preparing to enter the premises for an early meal.

The "closed" sign remained up at the Gourmet Plaza as prospective customers were turned away by police and asked to come back at a later time.

Seconded Cambridge police Inspector Trevor Tendall said: "We are acting on information received by a source.

"This is a joint operation involving police and immigration officers from across the county."

As prospective diners and onlookers watched, officers led out two men of Chinese origin in handcuffs, just before 7pm.

The pair were put into separate people carriers and driven away from the scene.

After the raid, an immigration officer, who did not want to be named, said: "We have acted and carried out the plan, and we are satisfied with the results today."

As the last of the officers left, five members of staff rushed out of the restaurant and across Cowgate to confront an officer in what was believed to be a dispute about a warrant.

When another member of staff found the piece of paper they were seeking, the staff filed back into the eaterie.

Customers, who had been told to go and have a drink in the nearby Drapers Arms, waited patiently on the street to see if the popular restaurant, with its all-you-can-eat £6.90 supper deal, would open its doors.

It re-opened at about 7.30pm.