A man and two women were arrested yesterday in an immigration raid on two suspected bogus colleges for foreign students.

The man, a college principal, was arrested on suspicion of obtaining leave to remain in the UK by deception while the two women, both college administrators, are suspected of breaching visa conditions.

Meanwhile, officers trawled through documents and computer files at the college site in Stratford, East London, while students were questioned over their visas and how long they had spent studying there.

The raid follows a series of revelations by The Herald about a network of bogus colleges operating across the UK, with several raising suspicions in Scotland.

In September, one such college in Glasgow was struck off an official government register which allows it to bring overseas students into Scotland.

Commonwealth College in Glasgow had been registered with the Department for Innovation, Universities and Skills for more than a year, clearing it to recruit foreign students on short-term visas.

However, the college was 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.

Yesterday's raid involved a team comprising 35 immigration staff, police officers, HM Revenue and Customs and Trading Standards officers and was part of an ongoing series of operations into potentially bogus colleges.

The intelligence-led operation targeted Monteagle College and Lloyds College, which were both operating out of the sixth floor of the same business centre.

The colleges, understood to be on the government's register of education providers, are thought to have about 600 students on their books.

However, officers found one empty classroom, no teachers and one student who had turned up to hand in a letter.

The government-run Border and Immigration Agency is investigating privately run colleges to check that they are not enabling people to remain in the UK without the correct visas or helping students who are using such colleges to stay in the country.

A student questioned by officers yesterday, who was from Bombay, India, said the fees for his business course were £4000 a year.

He admitted to officers: "I don't come regularly. I haven't been here for the last two weeks."

As the two arrested women were led away, officers were on their way to their homes to check their passports, marriage certificates and other documents.

In the midst of the raid, another two students arrived to register at the colleges. One, also from India, told officers he had already paid £3500 for a business course.

The agency will now check the visa status of all students registered at the colleges.

A spokesman said visas would be revoked from students if they were failing to attend classes.

Tony Smith, the agency's regional director for London and the South-East, said :"We would have expected to see a number of classrooms and teachers. There is one empty classroom, no teachers and one student. This is not operating as you would expect a college to operate."