The Conservative Harrow East MP who pledged to vote against any rise in tuition fees during the election campaign will break his promise today (Thursday) by supporting the coalition government's trebling of the student cap.

Bob Blackman is currently in parliament as secretary of state for business, innovation and skills, Vince Cable, explains to MPs why the government has decided to raise the cap on tuition fees from £3,290 to £9,000.

Up until Wednesday this week Mr Blackman was undecided on whether to vote for the rise, but he has contacted the Observer this afternoon to say: "I am supporting the government proposals as they reduce the amount paid by graduates, abolish up front fees and only start to be payable when graduates earn more than £21,000."

Asked for his response to students in the borough who may have voted for him on the basis that he would oppose any rise, as he promised on a visit to Harrow College during the election campaign, Mr Blackman said he thought the new system would be fairer.

"Graduates will pay far less than the present system. I ask them [students] to study the proposals to see that they are clearly a big improvement."

Joshua McKenzie, Harrow College Students' Union president, said earlier this week: "I was there along with over a hundred of my fellow students and staff when Bob Blackman signed his pledge.

"He needs to keep the promise that he made to those students and staff or he will not be trusted and these people will not vote for him again."

The tuition fee rise will help plug the gap in university budgets after Chancellor George Osborne's spending review announced cuts of 40 per cent to the higher education budget.

The NUS pledge, which Mr Blackman signed, states: "I pledge to vote against any increase in fees and to pressure the government to introduce a fairer alternative."