COMMONS Speaker Michael Martin will announce his resignation to MPs this afternoon - in a move expected to pave the way for a radical reform of parliament.

Speaker Martin’s dramatic gesture comes just 24 hours after he was publicly humiliated by a string of MPs calling in the Commons for him to quit.

He has become the highest-profile victim of the Westminster expenses scandal, which claimed another scalp today.

Tory MP Douglas Hogg, ridiculed for claiming for his country house moat to be cleaned, announced he would not be standing in his Sleaford and North Hykeham constituency at the next election in the wake of the row.

A spokeswoman for the Speaker said: "I can confirm that the Speaker is making a statement this afternoon and that it is about himself."

Mr Martin will go ahead later with his meeting with party leaders, including Gordon Brown, to discuss the expenses debacle.

Senior Labour MP Sir Stuart Bell, a member of the House of Commons Commission and a close ally of Mr Martin, said the Speaker was determined to push through radical change before he stepped down.

"He is determined to see through the reforms that he announced yesterday," he told BBC News.

"I can tell you the Cabinet this morning will approve a series of reforms which will place the House of Commons in the hands of independent regulators rather than the House itself.

"The nature of the role of the Speaker will change. There will no longer be a Speaker who is in charge as chief executive. He will be procedural and ceremonial."

Mr Brown’s spokesman confirmed that the Cabinet discussed "the reform of parliament" as well as arrangements governing expenses at its regular meeting this morning.

Many MPs welcomed Mr Martin’s move but others condemned it as the result of a witch hunt.

Labour backbencher Austin Mitchell said: "Tories have never liked him, but the main issue is fees and allowances. There has been a hue and cry whipped up by the Daily Telegraph and the House of Commons has given in to it.

"We have thrown them a bone and God knows who is going to be next."

News of the Speaker's intention to resign broke as a motion of no confidence in Mr Martin appeared on the Commons Order Paper for the first time, signed by 23 MPs.

Conservative backbencher Douglas Carswell, who tabled the motion, told Sky News: "I have acted not as his enemy and least of all as an opposition MP. I have acted as somebody who cares passionately for the parliamentary system.

"I believe we have found ourselves in a moral ditch and we need reform and change to get out of that ditch and restore dignity to politics.

"It gives me no pleasure to have done this at all, but it was necessary to do it. We need a new Speaker who understands that ’sovereignty of Parliament’ is shorthand for ’sovereignty of the people’.

Labour MP Paul Flynn, a signatory of the no-confidence motion, said Mr Martin had needed "this very sharp lesson from Parliament" to persuade him that he had to go.

"He just wasn’t getting it, even up until yesterday," Mr Flynn told Sky News.

"He could have gone with a great deal more dignity last week if he had got the message. I’m afraid he has brought this on himself.

"Parliament has to reform itself and he was the wrong person to lead it."

Liberal Democrat Norman Baker - one of the MPs publicly rebuked by Mr Martin over his criticisms of the way the expenses issue had been handled - said it was the "right decision" for him to step aside.

"I am afraid that the Speaker and the House of Commons Commission which he chairs has been the main obstacle to reform," he told the BBC News channel.

"They have blocked reasonable requests for information, they have spent vast amounts of money on court action to stop information coming out, they even tried to exempt MPs from Freedom of Information altogether."

Labour former Cabinet minister Frank Dobson said he was "distressed and to some extent disgusted" at what was happening to Mr Martin, whose efforts to keep the expenses system secret were backed by most MPs at the time.

Mr Dobson told BBC News: "It is a bit like a lot of people in a lifeboat slinging one person out in the hope that the water won’t now lap over us."

He added: "I think it is a dreadful example of the House of Commons as a whole - which as a whole is responsible for the mess we are in - trying to scapegoat one man who was trying to represent what he thought were their views on what should be done.

"Until about a fortnight ago, what he was trying to do did represent most members’ views."

Mr Brown, speaking after a meeting of Labour's national executive which discussed the expenses crisis, said it had unanimously decided that "no candidate, no Member of Parliament will stand for the Labour Party at the next election'' if they had "defied'' the rules on expenses.

The Prime Minister would not be drawn on the future of the Speaker, saying "it is not for the Prime Minister to tell the Speaker what to do".

But Mr Brown will hold his regular monthly press conference in No 10 at 5.30pm, when he will be bombarded with questions about Mr Martin’s resignation.

Tory former shadow home secretary David Davis, who also signed the motion, said it was time for the Commons to find "a new voice" but ruled out standing for the post himself.

Mr Davis said: "I commend the Speaker for putting Parliament before his own career.

"And I would stress that the need for a new speaker is more a reflection on the needs of Parliament than a reflection on him."

Mr Davis said the new occupant of the chair would be the "most powerful'' in history after being elected by secret ballot in the face of ``public anger'' over the expenses scandal.

"He or she will be expected to sort out not just the expenses scandal but all the other weaknesses in the House of Commons that have grown up over the years."

He said he was "categorically not" seeking the job himself and added: "If I had been interested I would not have been involved in the actions today."

Mr Davis said the new Speaker could well turn out to be somebody "completely unexpected".

"In a way this is a time for the House of Commons to find a new voice and that voice may not be the voice of the existing establishment."

The Scottish Labour Party said it could not confirm reports that local party figures were preparing for a summer by-election.

A spokesman said: "If there is a by-election we will of course prepare for it, but we have no knowledge of that.

"We will review the situation this afternoon when we know what the Speaker’s intentions are."

The speaker’s son, Paul Martin, a Member of the Scottish Parliament, declined to comment as he attended a Holyrood committee meeting in Alloa today.

Labour peer Lord Foulkes of Cumnock, a close ally of Mr Martin's, told the Press Association: "I am sure that whatever decision he announces will be in the interests of Parliament and of the country.

"If it is as has been reported, then I think the people who have hounded him out of office should hang their heads in shame at the despicable way that they have treated him."

Matthew Elliott, chief executive of the TaxPayers’ Alliance, said: "Michael Martin has been an awful Speaker and his arrogance and incompetence have betrayed the interests of taxpayers and Parliament, so his resignation is welcome.

"He has allowed MPs to get away with outrageous expenses claims, and wasted taxpayers’ money on legal action to try to keep those expenses secret.

"His resignation should be immediate, he should get no pay-off and he absolutely must not be elevated to the Lords. The next Speaker must have a commitment to full transparency and democratic accountability."