Michael Martin’s future as Speaker of the House of Commons looks likely to be decided tomorrow after both Opposition parties made clear they felt his position was untenable.

Nick Clegg became the first party leader in modern political history to call for a Speaker to resign, describing Mr Martin as a defender of the status quo and obstacle to the reform of Parliament.

William Hague, David Cameron’s effective deputy, said that the Speakership was “in crisis” and urged MPs to hold a vote of confidence in Mr Martin within days.

Downing Street have not commented, but the Government also seems to be cooling in its support for Mr Martin.

John Denham, the Skills Secretary, told Sky News that “we will respect the will of Parliament”, adding sensitivities in the relationship between Parliament and Government meant that he should not comment further.

Gordon Brown's spokesman has previously said that the Prime Minister thinks the Speaker is doing "a good job".

If Mr Martin is ousted, it will be the first time a Speaker has been forced out by a formal challenge since Sir John Trevor was sacked for taking bribes in 1695 during the reign of William of Orange.

The comments of the Liberal Democrats and Conservatives ignore a convention that the party leadership does not talk about the Speaker because it is seen as interfering with the independence of Parliament.

However they are a mark of the crisis surrounding the current Speaker, who could become the most high profile casualty to date of the furore over MPs expenses.

Parliament’s reputation is currently at its lowest ebb following the release of receipts submitted by MPs as part of their expenses claims. They show extravagant and in some cases possibly fraudulent claims, and the Speaker has become the focus of anger for failing to reform the system earlier.

Mr Martin could make a statement that he is resigning as early as today, in order to pre-empt a vote of no confidence. But his spokeswoman said that he would inform Parliament first of any decision.

Parliamentary figures are divided over whether the Commons will be able to vote on the confidence motion which is understood to have at least a dozen supporters.

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