Paul Smith, who will fight Bristol West for Labour in the next general election, has called on sitting MP Stephen Williams to quit.

He says Mr Williams – who took the seat for the Liberal Democrats with a majority of 5,128 over Labour' MP Valerie Davey in 2005 – won the election on the basis of opposing student tuition fees.

Mr Williams, Lib Dem spokesman on Innovation, Universities and Skills, is working to change the Lib Dems' policy on top-up fees.

The party is a committed opponent of the charges – about £3,000 a year – which were introduced by Labour as a way of funding increased places at universities.

But, as reported in Saturday's Bristol Evening Post, the Lib Dems are likely to abandon the policy.

Mr Smith said: "Stephen Williams made his opposition to tuition fees a main plank of his election campaign in 2005, in a seat with 20,000 university students.

"For the last year he has been writing plans for a U-turn. This act shows that he is prepared to make any promise to win the student vote.

"It is unlikely that he would have won the seat from Mrs Davey without this and he should do the honourable thing and stand down."

But Mr Williams said it was no longer sustainable and the party wants to find more immediate ways to help students.

Options being considered include non-repayable grants, changes to the bursary system and offering more money in student loans.

"This is an absurd request," he said.

"We are undergoing a policy review and the results won't be decided until my party's spring conference in Harrogate next March.

"We are looking to change the policy because circumstances have changed since 2005.

"Instead of students having to pay while they are studying, they pay afterwards and we now effectively have a graduate tax.

"That is broadly acceptable to people in a way that tuition fees policy, when first introduced, was not."

Mr Williams said the policy was not crucial on a local level, as a lot of students in Bristol West either did not vote locally or not at all.