Fraudsters working in London colleges are exploiting major flaws in the Home Office's new immigration system just months after it was launched, a BBC London investigation has found.
Under the new government system, students with advanced qualifications are allowed to live and work in the UK for up to two years.
But a BBC London investigation has shown that visas are currently being issued to immigrants whose qualifications are completely fake, which is exactly what happened under the old immigration system.
A seller of illegal visas was so fearless of the authorities he openly advertised his services online, on the Gumtree website.
The advert, posted by a man called Mr Rabbani, boasted anyone could get a visa for as little as £2,000.
The advert specifically offered post-study work visas - a new type of visa intended for highly qualified foreign students who can contribute to the British economy.
To get this visa, foreign students must have at least a post-graduate degree or diploma from a college that is recognised by the Home Office.
What Mr Rabbani's advert failed to mention was that students could enrol at these colleges and receive their post-graduate qualifications within a matter of weeks, without ever having to study.
BBC London sent an undercover reporter wearing a hidden camera to meet Mr Rabbani, posing as a Somali immigrant with no qualifications and no intention of studying.
Do you want to study or do you just want the certificate straight away
Mr Rabbani asked the undercover reporter: "Do you want to study or do you just want the certificate straight away?"
When the reporter said he wanted it straight away, Mr Rabbani replied: "I will get you the certificate. When you feel ready you can pay the money."
The undercover reporter quizzed Mr Rabbani over how a dodgy certificate could be enough to fool an officer from the Home Office's Border Agency.
Mr Rabbani insisted he had managed to get visas for hundreds of students, because his service involved more than just paperwork.
In addition to the certificate, Mr Rabbani said he would also put the reporter's details into the computer system of an accredited college and back-date this information to make it look like he had studied there for years.
Mr Rabbani claimed some colleges were in on the scam
Mr Rabbani said he could access the computers of accredited colleges because the bosses of those colleges were in on the scam.
"We know four or five colleges, because we know the directors personally. We are working for them."
He said the total cost would be £2,200 which could be paid to the college rather than directly to him.
Of this money, he would personally take £200, while a college administrator would take £200, he said.
Another £250 would go to a lawyer to "certify" the documents and the rest would go the college directors.
Mr Rabbani told the undercover reporter the Home Office recently raided one of the colleges in his network.
I'm only offering genuine certificates
But he said he was unconcerned and that he would simply put the undercover reporter through a different college instead.
The raided college cannot be named for legal reasons, but the police and the Border Agency have confirmed that the raid took place.
They say they uncovered evidence that the college had been used for as many as 2,500 fraudulent visa applications in the past six months - which would have netted the fraudsters at least £5m.
The scale and apparent simplicity of the scam will be an embarrassment to the government.
Just last month Immigration Minister Phil Woolas claimed the new immigration system represented the "biggest shake-up for a generation".
But Tony Smith, Regional Director for the Border Agency, said the new system was in a "transitional phase" but he was aware there were a small minority of colleges straying into immigration organised crime.
"The new system is just being rolled out now," he said. "We are systematically checking colleges that want to register with us to bring foreign students into the country.
"This is a transitional phase from the old system into the new."
He said the raided college was checked at the same time it was visited by the undercover reporter but that it had not registered to bring in foreign students into the country.
The fraudulent qualifications are advertised online
He said all establishments that wanted to bring foreign students into the country needed to register with the agency before next March.
Visa scams in the past tended to involve small backstreet establishments which posed as colleges solely for the purpose of fraud.
Over the past year, since BBC London exposed an international education scam involving conmen in Oxford and Cambridge, many bogus colleges have been weeded out and removed from the Home Office's list.
But far from giving up, it appears alleged visa fraudsters like Mr Rabbani have merely adopted a new strategy - infiltrating real colleges with real students and lecturers.
Secret filming revealed the details of the alleged visa scam
These colleges cannot be named for legal reasons, pending investigation by the Home Office.
However, they are all surprisingly large and reputable institutions. A number of prominent people with links to these colleges are likely to come under the spotlight once the authorities complete their investigation.
When BBC London's Special Correspondent Kurt Barling confronted Mr Rabbani about his activities, he denied involvement in issuing fakes and said he offered genuine certificates.
"I'm only offering genuine certificates. I'm just helping the students to get the certificates…I'm not taking money from a single person," he said.
He said that "commission-wise" he's "just helping the students" to get the certificate.
A source, who asked not be named and who knows people inside the illegal network, described long queues of immigrants outside one of the colleges last Friday night.
"The college closed normally at 1800," they said. "Then it opened again at 1900 and it stayed open until as late as 0300, taking money from immigrants and printing their paperwork.
"There were certificates and piles of cash all over the place."
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