Centuries of self-regulation to end | PM's secret meeting with Martin | Reaction | 'Moat' MP to step down | Labour to discipline MPs | Vote for next speaker | Runners and riders | Profile: Michael Martin | Archive: disgraced Speaker, 1695 |

Michael Martin announced his resignation as Speaker of the House of Commons today, swept away by the expenses scandal engulfing Westminster. He is the first Speaker to be forced from office for more than 300 years.

The veteran Glasgow MP had effectively sealed his own fate when stubbornly refused to countenance discussion of his own future during a Commons statement yesterday. As a string of senior MPs stood up to demand his resignation, his authority crumbled away.

This afternoon, after bowing to the inevitable, Mr Martin again addressed a packed House to lay out the timetable for his departure. His statement lasted less than a minute before the Commons passed on to other business.

"Since I came to this House 30 years ago, I have always felt that the House is at its best when it is united," he said.

"In order that unity can be maintained, I have decided that I will relinquish the office of Speaker on Sunday June 21. This will allow the House to proceed to elect a new Speaker on Monday June 22.

"That is all I have to say on this matter."

Within hours of announcing his resignation, Mr Martin was due to return tonight to the Commons to announce to MPs an agreement between all three party leaders to end centuries of self-regulation.

In a press conference this evening, Gordon Brown said an agreement had been reached in principal over the introduction of an independent statutory body to oversee the rules governing MPs expenses and pay. The statement was due to take place at 7.20pm.

As he steps down from the Speaker's chair, Mr Martin will also be standing down as an MP – leaving a vacancy in his constituency of Glasgow North East.

Under electoral rules, the party that holds a vacant seat has the right to choose the date for a by-election but in this case the Speaker no longer represents the party, Labour, for which he was first elected 30 years ago.

It is assumed at Westminster that the decision over timing will nevertheless fall to Labour, which will move quickly to call a by-election to avoid giving the Scottish National Party, which stood against Mr Martin in 2005, even longer to prepare its campaign.

Times Recommends

• Fern Britton: 'I still can't see that I was wrong'
• Extreme cooking
• Easy French: Tarte Tatin