British detectives launched a nationwide crackdown on the "21st century slave trade" in illegal immigrants today arresting 40 people in a series of co-ordinated dawn raids.
Police said those being held included a Ukrainian man in his 40s who officers believe to be one of the biggest illegal gangmasters in the country.
In an operation led by Norfolk police, scores of officers from Norfolk, Aberdeen, Cambridgeshire, Essex, London and the Immigration Service raided addresses or executed warrants to make arrests and gather evidence.
By mid-morning 38 people had been detained in Scotland and two in Norfolk.
"Six were arrested on suspicion of facilitating the entry of illegal immigrants into the United Kingdom and their subsequent residency and also for money laundering under the Proceeds of Crime Act 2002," said a spokesman for Norfolk Police.
"Four men, 'lieutenants' in the organisation, were also arrested."
He added: "Those arrested included a Ukranian man in his early 40s from the King's Lynn area who is believed to be one of the biggest illegal gangmasters in the country."
Detective Inspector Paul Cunningham, who is leading the investigation, said: "Our aim was to stop immigrants, some legal, some illegal from being abused. These people are modern-day slaves, working 15 hours days, living in overcrowded, unsuitable conditions and paid a pittance for their trouble whilst their gang masters live in luxury and launder the profits."
He added: "Gangmasters working illegally cause real misery for vulnerable people, who live in over-crowded conditions. This is the 21st century slave trade."
Police believe that the Ukrainian man arrested in King's Lynn is a father of two young children who came to England as an asylum seeker about four years ago.