More than 60,000 bogus students could have entered the UK last year, campaigners claimed on Tuesday.
There is clear evidence of abuse on a major scale, with government figures suggesting more than 44% of the 141,700 overseas students who came to the UK last year could be bogus, a report by Migration Watch UK said.
Sir Andrew Green, the group's chairman, said: "Bogus students come here to work illegally and thus take jobs from British workers.
"We now have clear evidence of abuse on a major scale."
Home Secretary Theresa May is bringing in risk-based interviews of up to one in 20 potential international students from the end of the month after a three-month pilot scheme.
It found 32% of almost 2,000 students from outside the EU who were interviewed and granted a UK visa would have been denied one if UK Border Agency (UKBA) officials had the power to refuse visas because they suspected the applicant was not a genuine student.
Using the refusal rate for each country in the pilot scheme and applying it to applications made in 2011, Migration Watch found 63,069 applications could have been refused last year.
Among the countries in the pilot scheme where abuse appeared the most prolific, Burma had a refusal rate of 62%, India, Bangladesh and Nigeria all had refusal rates of 59%, and the Philippines 53%.
Migration Watch also claimed the Government "bottled out on bogus students" by failing to include questions over whether the applicant intends to return home after their studies in the new interview scheme.
The Home Office insisted potential students would be asked "searching questions" to determine whether their applications were credible, but would not fail the test if they had "sensible plans to extend their stay or work under the current rules".
Sir Andrew said: "These half measures simply will not do. The Government have bottled out on bogus students.
"If they are serious about immigration they must face down the self-interested demands of the higher education sector and pursue the public interest."
He added: "If it is clear from the circumstances that a student is unlikely to go home, the visa should not be granted in the first place.
"After all, many of the advantages claimed for foreign students depend on their going home after their studies."
But Immigration Minister Damian Green said: "We have radically reformed the student visa system precisely to weed out abuse and protect the UK from those looking to play the system.
"This includes interviewing applicants and giving officers the power to refuse visas if they are not satisfied the applicant is genuine.
"Applicants will be asked a variety of questions designed to assess their intentions and determine whether they are credible. We will keep the assessment criteria under review."
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