Twickenham MP Vince Cable has denied the Liberal Democrat party has broken promises on university tuition fees.

The Business Secretary insisted the Liberal Democrats’ election campaign pledge to oppose any rise was not binding because they were part of a coalition Government.

He said on the BBC’s Politics Show that the party had not betrayed students, adding that many did not understand the proposals.

Rioters who marched through central London earlier this month are planning further protests tomorrow as part of a national day of action.

Dr Cable said: “I think a lot of the people who are protesting actually don’t understand what’s being proposed.

“It doesn’t actually affect them - we’re talking about a system of graduate contribution that will only affect people who start going to university in a couple of years’ time.

“If they are concerned for the next generation what I think they do need to understand is that we’re making the system significantly fairer, making it much more attractive for part-time students and for graduates on low incomes.”

He accepted the Liberal Democrats’ pledge may not have been a wise political move, but said students should not think the party was no longer trustworthy.

He said its main commitment was to honour the coalition agreement with the Conservatives.

He said: “We didn’t break a promise. We made a commitment in our manifesto, we didn’t win the election. We then entered into a coalition agreement, and it’s the coalition agreement that is binding upon us and which I’m trying to honour.”

The Government plans to allow universities to charge up to £9,000-a-year from 2012.

Deputy prime minister Nick Clegg, who said during the election campaign that raising tuition fees would be a “disaster", has also admitted his party should have thought twice before making its pledge.

Siobhan Bellot, president of the students union at St Mary's University College, in Waldegrave Road, Twickenham, said she thought it was “just as important” for the Liberal Democrats to follow through with their pre-election pledges as it is to honour the coalition agreement.

She said: “It’s because of those pledges that they were elected. I do think that he [Vince Cable] is breaking it because he is going back on his word. He said they would do all this and now they are in power they’ve let it all go really.”