Ministers say most foreign students will not be put off

Currently, those from outside the EU must pay £155 to extend their visas by post, or £250 for a fast service if they need to stay to finish a course.

But from April they will have to pay £250 for the postal service, or £500 for the "premium" in-person service, immigration minister Des Browne said.

Vice-chancellors' group Universities UK said it was "very disappointed".

'Detrimental'

Its president, Professor Ivor Crewe, has written to Tony Blair warning that increased visa costs could deter applicants and strip institutions of much-needed income.

He said: "Introducing charges at this level could have a detrimental impact on international student recruitment."

The new postal rate is £85 cheaper than that for non-student visas, which rises to £335.

In a written Commons statement, Mr Browne acknowledged that overseas students brought "economic and social benefits to the UK".

He added: "In recognition of this, students seeking to vary or extend their conditions of stay in the UK will be charged a reduced fee for postal applications."

Mr Browne said increased visa fees "were unlikely to have a significant impact on the UK's ability to attract and retain international students".

"However, in order to ensure that remaining to study in the UK remains a competitive option, we have decided that charges should be at a lower rate of £250 for the standard postal service."

Prof Crewe called for a full review of the impact of the changes by the end of this year.

He said: "It is particularly important that, if the adverse effect of higher charges is what we predict, the government should undertake to look again at the level of charges."

The British Council predicts the number of overseas students wanting to attend UK universities could triple to more than 870,000 by 2020.