Sixty-seven students received visas after paying around £500 each to join courses at a bogus college uncovered in investigations by The Herald.

The revelation is the first time the scale of operations at such a college - and the likely financial gain - has been uncovered.

A request under Freedom of Information legislation shows that 67 students were given visas to remain in Scotland in the academic year 2006-2007 by the Borders and Immigration Agency after signing up for courses at Commonwealth College in Glasgow.

UKvisas, a branch of the Home Office which issues visas to students coming into the country, does not keep accessible records of which educational establishments those students are attending but a Home Office source said the college had admitted to having 25 first-time overseas students last year.

The Herald understands that a minimum charge for a visa would be at least £550, netting Commonwealth College more than £50,000. However, students could be charged much more - possibly even thousands - depending on how long they want to stay. Commonwealth College has so far filed no accounts for the last financial year.

The college was allowed to bring in overseas students after being registered on a list of approved providers operated by the Department for Innovation, Universities and Skills (DIUS).

However, the college was subsequently removed from the list shortly after The Herald uncovered a series of discrepancies in courses it was offering and false claims made on its website about affiliations with professional bodies.

Two of those organisations - the Association of Chartered Certified Accountants and the Chartered Institute of Management Accountants - said they had no connection with Commonwealth College.

The college's Glasgow prospectus even featured photographs of Manhattan in New York and and Central Square in Brussels rather than images of the city where it was based.

The existence of Commonwealth College, and hundreds of similar unlicensed colleges across the UK, have fuelled fears that fake institutions are routinely used as a front for bringing illegal immigrants into the country under student visas.

Last night, Murdo Fraser, education spokesman for the Scottish Conservative Party, who has raised the matter of bogus colleges in the Scottish Parliament, said: "It is absolutely essential that action is now taken against these colleges to prevent this abuse of the immigration system."

Howard McKenzie, acting chief executive of the Association of Scotland's Colleges, also expressed concern over the issue, claiming it once again illustrated the need for the UK Government to restrict use of the term "college".

The ASC has already written to Des Browne, Secretary of State for Scotland, calling for the 1985 Business Names Act to be changed to include protection of the term "college".

The act currently protects the names "university", "polytechnic", "institute" and "special school" and only those who have approval from the Secretary of State can use such terms. However, "college" is not protected.

In a separate development, the LSMT Business School in Glasgow has insisted that detailed advice on its website to help overseas applicants pass the UK entry interview is entirely legitimate.

As The Herald reported in September, the school's prospectus states: "It is vital to rehearse what you are planning to tell by anticipating the interview questions and simulating real-life answers."

However, Waseem Kazmi, an LSMT official, said the information had been taken out of context.

"Our advice is strictly to help them choose the course and then prepare for the consular interview so they will have a better chance to study in the UK and start building their futures," he said.

"It is stated obviously on our website to be truthful during consular interviews."