One of the UK's biggest immigration scams has been unearthed after a series of trials.
Yusuf Mewaswala from Leicester was one of the leaders of the UK scam
Thousands of Indian nationals were brought to England illegally using fake South African passports.
Details of the criminal network were given by the Serious Organised Crime Agency (SOCA) as six people were convicted at Leicester Crown Court.
Leicester was the centre of the smuggling network which brought illegal immigrants in via South Africa.
The immigrants were charged as much as £30,000 for the service.
Once through customs, many of the illegal immigrants were kept in safe houses in London until they found work or further accommodation predominantly in Leicester, Bolton, Blackburn and Preston.
Others were assisted by a corrupt Heathrow Airport official in continuing on to Canada or the United States.
The UK arm of the gang was led by two men - Yusuf Mewaswala, 49, from Leicester and Harekrishna Maganbhai Patel, 38, from Brighton.
A string of inter-linked investigations was triggered by the discovery of a fake passport factory under stairs at a property in Leicester in September 1999.
The court heard how once "clients" travelling from India reached South Africa they would pay about £500 for a genuine South African passport fraudulently issued by corrupt officials and use these to enter the UK.
Anyone travelling to Britain with this passport did not need to get a visa to come in as a visitor for six months.
Many of these then registered with colleges or became involved in sham marriages to extend their stays, SOCA said.
Both Mewaswala and Patel, who held previous convictions for people smuggling, were sentenced in 2007 and 2006 respectively.
Mewaswala, pleaded guilty last year as part of Operation Coptine to people smuggling offences and was given 10 years behind bars.
Patel was sentenced in 2006 to 10 years in jail, another deportation order and a £100,000 confiscation order.
Details of the criminal network were only announced on Monday by SOCA, following the lifting of reporting restrictions at Leicester Crown Court.
On Monday, Sajid Bhikhi, 40, and Asif Bhikhi, 38, both of St George's Square, west London , and Soyab Patel, 25, of Boleyn Road, north London, were jailed for five years after they were found guilty of conspiring to facilitate illegal entry into the UK.
Sikander Patel, 36, of Osborne Road, Leicester, was jailed for three-and-a-half years for the same charge plus obtaining leave to remain in the country by deception and possessing a false South African passport.
Asif Patel, 32, of Croston Road, Bolton, will be sentenced at a later date after being found guilty of the same conspiracy.
Sabbir Patel, 31, of Mallory Place, Leicester, was jailed for two-and-a-half years after admitting his part in the operation.
Sentencing them, Judge William Everard said: "This conspiracy involved a professional and sophisticated operation."
"I am quite satisfied that using those passports, people were illegally coming to the UK.
"People would then apply to go to college, thereby enabling them to extend their stay in this country. They never went to college at all but just used it as an avenue to stay longer in this country," he added.
Officials are now trying to track down illegal profits made from the scam.