Boris Johnson has warned the Government not to be prejudiced against foreign students who want to study in the UK.
Speaking ahead of an address to Indian students in Delhi, the London Mayor said new rules introduced last year by ministers to slash the number of bogus colleges sent out the "wrong signal", adding that he feared they would hit the £2.5 billion revenue stream British universities earn from overseas students.
The industry played an important part in subsidising domestic undergraduates, the mayor said, as he announced plans to set up an Education Export Commission with central Government to examine whether foreign students were now choosing to study in the United States, Canada and Australia instead.
Mr Johnson has been a vocal opponent of the new restrictions, which include higher standards of English literacy and refusing overseas graduates the right to stay in the UK unless they can secure a job with a salary above £20,000.
According to Mr Johnson's figures, the number of Indians applying to study in the UK dropped 9% this year and is forecast to fall a further 25% next year. Of the 110,000 foreign students in London alone, 9,000 are from India, where Mr Johnson is spending this week trying to build business links with the capital.
In interviews ahead of a speech to prospective students at Amity University, the equivalent of Oxford or Cambridge, Mr Johnson said he was worried the "mood music" from Whitehall was putting the very best off applying.
He said: "We are going to set up with Government an Education Exports Commission to look at the issue to make sure we get the right message across so that if the Government decides to make changes to the visa regime it doesn't do damage to a sector in which London is so strong and it is so valuable.
"The vast majority of Indian students do get a visa, 75% of them get one pretty much straight off. It's more of a perception at the moment. The policy on visas is, in my view, sending out the wrong signal. There are so many stipulations that we are starting to lose business to Australia, America and Canada."
In a letter to Home Secretary Theresa May, Mr Johnson said he wanted student visa statistics to be removed from the overall net migration target of less than 100,000. The Migration Advisory Committee must also look at the economic impact of the Government's policy on student visas, he said.
Mr Johnson wrote: "To mitigate future reputational risks, safeguards need to be in place to protect the investment international students make when choosing London and the UK as their destination. I would ask that you introduce new measures in the student visa system to protect genuine students from circumstances when a sponsor loses its licence. These measures should include as a minimum permission to complete studies or the academic year, whichever is soonest."