An undercover investigation by BBC Newsnight has exposed fraud at the heart of the student visa system.
The programme was able to buy two bogus visa documents which would have virtually guaranteed entry to the UK. One cost £200, the other just £150.
Overseas students coming to study in Britain have to obtain a formal invitation from one of nearly 2,000 colleges on an approved list run by the Home Office.
These official documents, called visa letters, are issued by a range of institutions, from major universities to tiny private colleges in rows of shops.
Under the UK Border Agency's points-based system, a visa applicant requires 40 points to get into the country.
Thirty points come from having a valid visa letter for a UK college. Another 10 are awarded for having several thousand pounds in the bank for 28 days - which could easily be borrowed.
Information from a source prompted Newsnight to investigate a small, private college in west London called Gateway2uk Education. The college, with a campus at Hayes, has been operating with an A rating from the UK Border Agency.
But Newsnight was told that people linked to the college were selling bogus visa letters for cash from a secret office in Wembley Park in London.
Newsnight set up a covert observation point nearby and filmed deals taking place. We watched as a succession of young men came and went. One even counted his cash outside. They left with A4 white envelopes.
Using undercover researchers, we then managed to buy two bogus visa documents and filmed the process. One of these was sold by a former administrator at Gateway2uk Education.
The administrator later went to India. When traced there by Newsnight, they said they bitterly regretted getting involved in the fraud and had been a minor player, directed by the then owner of Gateway2uk Education, Indian entrepreneur Darpan Shah.
Darpan Shah denies this account. Through his solicitor he said he had very little overall control of the business and he could not comment on the activities of the administrator who sold us the documents.
His solicitor told us: "Mr Shah would like to make it abundantly clear that he has played no part in the sale of bogus visa letters."
'No knowledge of fraud'
Darpan Shah says he only owned Gateway2uk Education for 25 days in January. But he was a director until 5 February 2010 and Newsnight's bogus letters were bought while he was still there.
Newsnight took the bogus visa letters to the Hayes campus of Gateway2uk Education to ask the academic principal for his reaction.
Principal Jeremy Coulton was visibly shocked, saying he had no idea that visa letters were being forged.
The following day he found a box full of bogus visas - almost 160 - which had been left in the office. They were sent from a company in Baroda in India called Krish Immigration. The company is owned by Darpan Shah.
Mr Shah told Newsnight he has "no operational control" over Krish Immigration and has "no knowledge of fraud".
He said: "There has not been any allegation of wrong-doing previously," adding that "Krish Immigration prevents forgery and fraud".
Mr Shah says he has been unwittingly caught up in two frauds, in the UK and India. On both occasions, he argues, people working with him have acted wrongly without his consent. He says he has now sold the Gateway2uk Education college.
Earlier this month, as Newsnight was finalising its investigation, the UK Border Agency suspended Gateway2uk Education's licence to take in new students. Its premises were inspected on Tuesday.
Two other colleges with close links to Darpan Shah have also had their licences suspended pending further inquiries.
On Monday the government introduced a new electronic system to help tackle student visa fraud.
But given the huge sums of money involved - £8bn a year - the industry will continue to attract those who seek to exploit weaknesses in the system.
Watch the full report on Newsnight on Wednesday 24 February 2010 at 2230 on BBC Two, or afterwards on the BBC iPlayer.