Former Education Secretary Shirley Williams has ruled herself out of running to become chancellor of Oxford University in a protest against top-up fees.

Baroness Williams said she would have loved to have succeeded her late Liberal Democrat colleague and fellow SDP founder Roy Jenkins in the job.

I simply could not argue two things at once Shirley Williams Lib Dem peer

But taking up the post would have presented a conflict of interest in the wake of the government's decision to allow top universities to charge more, she said.

As a firm believer of students being chosen on merit, not means, she could not head up a university which would want to levy higher fees, she said.

It was announced on Friday that the election for the new chancellor will be held on 14 and 15 March, when all of Oxford's 100,000-plus graduates will be able to vote.

The election will use the single transferable vote system.

That is a form of proportional representation of which Lord Jenkins would have approved, although he would not have won in 1987 had it been in place then.

'Famished'

Lady Williams, herself an Oxford graduate who has taught extensively at Harvard, was one of the favourites for the lifetime role of chancellorship.

The Lib Dem leader in the House of Lords said many Oxford graduates, as well as some of the heads of the university's colleges, had offered their support if she became a candidate.

She told BBC Radio 4's Today programme the university had been "famished" for years and desperately needed more money.

"The university will understandably want to maximise its top-up fees," she said.

Bill Clinton appears to have ruled himself out

That would present problems for someone "who believes that the idea of a two-tier university is profoundly wrong and that youngsters should be not chosen on the grounds of their means, but on the grounds of their merit".

"I simply could not argue two things at once - one for the university as chancellor and one in the capacity of believing that this new higher education proposal is profoundly wrong," continued Lady Williams.

Education Secretary Charles Clarke this week announced universities would be allowed to charge up to �3,000 a year for undergraduate courses.

Payments would, however, be put on hold until students left university and started earning at least �15,000 a year.

But it is estimated the changes could leave the average graduate owing �15,000.

Election rules

Lady Williams argued that American top universities like Harvard chose students regardless of their means.

Scholarships and endowments were then used to help those from poorer backgrounds, she argued.

Her decision not to stand for the post follows reports that her candidature faced resistance from some Oxford dons.

Graduates of the university are invited to nominate people for chancellor - and proposals then need to be supported by 50 other graduates.

The chancellor, a non-paid post, is not required to be resident at the university, although he or she would be expected to be available for a number of formal and ceremonial duties each year.

Leading contenders?

No nominations have yet been received but former US President Bill Clinton has been seen as one popular contender.

But Mr Clinton, who studied at Oxford and whose daughter Chelsea is now a student there, appears to have ruled out the idea.

His New York office has said: "He is very busy with the work of his foundation and this is not something he's considering."

Former Conservative Party Chairman Chris Patten, now a European commissioner, is viewed as another possible contender.

Lord Bingham of Cornhill, the senior law lord who is already High Steward of the university, is among other high profile possible candidates.

Former Deputy Prime Minister Michael Heseltine and ex-Cabinet Secretary Robin Butler have also been mentioned for the job.