Prime Minister Gordon Brown will speak to reporters at 5.30pm BST following the resignation of Michael Martin as Speaker of the House of Commons.
Watch here for live coverage. (Also watch STV news at Six on STV television at 6pm for full coverage and analysis.)
Mr Martin made his historic announcement earlier on Tuesday. Uttering only 71 words, he told a hushed audience of MPs his plans to leave the chair on June 21 and set into motion a vote to determine a successor the next day.
Overnight Mr Martin reflected on his position amid a growing rift over the handling of expense claims reported by MPs. The Labour MP then spoke with Prime Minister Gordon Brown on Tuesday morning.
STV news reported the story first - at 10.15am on Tuesday.
Mr Martin will become the first Speaker to be forced from his post in more than 300 years. Sir John Trevor was ousted from the office in 1695 after the House of Commons found him guilty of "a high crime and misdemeanour" for accepting a bribe.
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RESOURCES
Michael Martin: From shop steward to Speaker
The Speaker - a historical perspective
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The Speaker's future was left in the balance following extraordinary scenes in the Commons on Monday when a series of MPs rose to demand he stand aside or submit to a vote of no confidence.
Despite saying he was "profoundly sorry" for his part in what had happened, he showed no indication that he was prepared to go.
The UK Government had resisted pressure to allow a Commons debate on a motion of no confidence in Mr Martin tabled by the Tory backbencher Douglas Carswell. That motion had been backed by 23 MPs by Tuesday morning.
Faces of Frustration: Michael Martin in a challenging day as Speaker
Speaking in Westminster on Monday, he said all members bear responsibility for what had happened and they all must work to restore the trust of the voters. He added: "We all bear a heavy responsibility for the terrible damage to the reputation of this House. We must do everything we possibly can to regain the trust and confidence of the people."
He urged all MPs not to submit expenses claims for approval until interim reforms had been agreed and said an early day motion calling for him to be replaced was not "substantive". Mr Martin also refused to say whether he would be stepping down before the next general election.
His statement did little to quell anger among MPs. Conservative MP Richard Shepherd urged that the motion of no confidence in Mr Martin should be debated, but the Speaker said that was a matter for the UK Government.
Liberal Democrat leader Nick Clegg was the first party leader to add his voice to those calling for him to go, saying Mr Martin had "dragged his feet" in reforming the system.
Mr Martin, MP for Glasgow North East, angered critics by trying to block publication of MPs expenses and failing to push reforms of the system. He came under renewed fire last week for rebuking MPs who questioned his approach.
Previously, he had faced criticism over his family's claims for allowances, as well as facing high-profile questions over why police were allowed to search Conservative MP Damian Green's office without a warrant.
Last updated: 19 May 2009, 18:56
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