'The Yorkshire Jamie Oliver' in trafficking ring

Staff came from the Middle East, India and Pakistan to work at the Rajput restaurant in Harrogate, heading to the UK legitimately after signing formal contracts and obtaining work visas.

But, after arriving in North Yorkshire, they had their passports taken from them and were put to work for up to 14 hours a day, seven days a week.

Their ordeal ended when the Yorkshire immigration crime team, comprising UK Border Agency (UKBA) officers and police detectives, raided the restaurant in November 2008.

During its investigation, codenamed Operation Keepnet, the team uncovered the exploitation of nine men at the restaurant, in Cheltenham Parade, dating back to 2004.

Yesterday, after a three-month trial at Leeds Crown Court, three members of the family which owns the restaurant were convicted of conspiring to traffick people into the UK for the purpose of exploitation.

Parveen Khan, 55, and her sons Shahnawaz Ali, 30, and Raza Ali, 33, all of Green Lane, Harrogate, will be sentenced at a later hearing.

The trial heard Parveen Khan had founded the restaurant in 1992 and remained closely involved its running after her sons became directors.

Head chef Shahnawaz Ali Khan, once dubbed the "Indian Jamie Oliver", looked after work permits while Raza Ali Khan was in charge of pay.

The nine staff claimed they were effectively barred from moving around freely, forced to share accommodation with other staff and taken to work by their employers so they could not run away.

Prosecutor Christopher Tehrani told the trial one desperate worker contacted his wife and she informed the authorities in India about what was happening. They then got in touch with officials in the UK.

Another man, Ghulam Mustafa, was so disturbed he fled Harrogate and went to a police station in Bradford in January 2008, while three more ran way in August 2008 and turned up at Huddersfield Police Station.

One employee said his visa and photo had been ripped out of his passport, and Pakistani chef Babar Hussain claimed Parveen and Shahnawaz Ali Khan called him names like "donkey face", "dirty liar" and "son of a dog".

Of the nine men, three have returned home and six have remained in the UK legally.

Their allegations were challenged by barristers for the three defendants, who branded the claims "ridiculous", "exaggerated" and "frankly laughable".

But the jury returned unaninmous guilty verdicts against Shahnawaz Ali Khan and Parveen Khan, and convicted Raza Ali Khan by a 10-2 majority.

Helen Gaunt, of the Crown Prosecution Service, said the case was "difficult and complex" and one of the first of its kind.

"It was unusual," she added, "because the workers involved were legal foreign nationals, who had then been deliberately trafficked into the UK by their employers.

"Behind the conventional faade of a well-known Harrogate restaurant a litany of gross exploitation for the purpose of financial gain was discovered.

"We hope it is some small comfort to the victims that justice has now been served in this case, and that they can now go on to rebuild their lives."

The UKBA has monitored the Rajput for years, and as recently as last December it was raided by officers who found three people working illegally. The managers were fined up to 30,000.

UKBA regional director Jeremy Oppenheim said: "This case goes to show that immigration crime does not pay and that those behind it can be involved in all sorts of crime.

"Let me be clear: Immigration crime exploits vulnerable workers, honest businesses and the UK taxpayer and, as this case demonstrates, the UKBA will target those involved and bring them to justice."