The Speaker of Britain's lower house is to step down in June following calls for his resignation over an expenses scandal that has tarnished the reputation of parliament.
Michael Martin, 63, becomes the most senior figure to step down after parliamentarians' expense claims for everything from manure to porn films triggered outrage across Britain and opposition calls for an early general election.
"In order that unity can be maintained, I have decided that I will relinquish the office of speaker on Sunday, June 21," Martin said in a short statement to a packed parliament.
Parliament will elect a new speaker, who could come from any of the major parties, by secret ballot on 22 June.
The last speaker forced from the post was John Trevor, who lost the confidence of the house in 1695 for taking a bribe.
The speaker is parliament's most senior official and his departure escalates the crisis engulfing British politics.
Mr Martin has been criticised for opposing transparency on expense claims by MPs but some lawmakers said he was being made a scapegoat for parliament's failings.
A series of reports in the Daily Telegraph newspaper, based on leaked information, detailed how members milked the expenses system to supplement an annual salary of around 65,000 pounds.
In a rebuff to parliamentary officials who alerted police to the leak, police said on Tuesday they would not investigate.
Claims included everything from bathplugs and biscuits to cat food and tennis court repairs.
National newspapers also joined a chorus of voices telling Mr Martin to step aside so that someone new could push through reforms.
Political crisis deepens
The Speaker's departure escalates the crisis engulfing British politics.
Conservative Party leader David Cameron, who is well ahead in the opinion polls before a parliamentary election due by June 2010, said a "very angry" public was more concerned about having an early chance to vote than the choice of Speaker.
Prime Minister Gordon Brown, grappling with the worst recession since World War II, is expected to resist calls for an early election.
Mr Brown has called for fundamental reform of the expenses system to try to defuse a scandal that has damaged all the main political parties but is hitting his own Labour Party hardest after 12 years in power.