Sir Jeffrey Donaldson has been charged with historical sexual offences and has quit as Democratic Unionist Party (DUP) leader.
Sir Jeffrey has been suspended from the DUP pending the outcome of the judicial process and Gavin Robinson has been appointed interim party leader.
The party said it had received a letter from Sir Jeffrey stating that he had been charged with allegations of a historical nature and that he would be stepping down as leader.
It is understood that Sir Jeffrey is facing one count of rape, one count of gross indecency, and several counts of indecent assault.
It is further understood that in a letter to party officers, he made clear he would be “strenuously contesting” all charges against him
In a statement, the DUP said: "In accordance with the party rules, the party officers have suspended Mr Donaldson from membership, pending the outcome of a judicial process.
"The party officers have this morning unanimously appointed Mr Gavin Robinson MP as the interim party leader."
Mr Robinson described the news as a "devastating revelation" and a "tremendous shock".
But speaking to Sky News, he criticised "some who have sought to score cheap political points".
He said the party became aware of the allegations “very late” on Thursday.
Mr Donaldson has not resigned as MP for Lagan Valley and his successor did not rule out a by-election, saying: "What comes in the days and months in that regard are outside our control".The shock announcement comes just weeks after Sir Jeffrey made the decision to bring the party back to powersharing in Northern Ireland.
Police issued a statement on Friday morning, but did not disclose the identity of those charged.
The statement said a 61-year-old man had been charged with "non-recent sexual offences" adding that a 57-year-old woman was also arrested at the same time and charged with "aiding and abetting additional offences".
The statement also confirmed the pair would appear before Newry Magistrates' Court on 24 April.
Overnight, Mr Donaldson's website and social media accounts, including X, Facebook, Instagram and LinkedIn pages were deleted.Sir Jeffrey's leadership saw him steer the party's two-year boycott of Northern Ireland's political institutions in protest over post-Brexit trading arrangements.
After protracted negotiations, the DUP agreed to return to Stormont in February following the agreement of a new deal and a series assurances around Northern Ireland's constitutional position within the United Kingdom.
Sir Jeffrey, who has had an almost 40-year career in politics, became DUP leader in July 2021.
His career started with the Ulster Unionist Party (UUP) and in 1985, aged 22, he was the youngest person to be elected to the Northern Ireland Assembly.
The 61-year-old's relationship with former UUP leader David Trimble deteriorated when he led a walkout of the 1998 peace talks after opposing the early release of republican and loyalist prisoners.
He left the party and joined the DUP in January 2004.
He was recognised by the Queen in her 2016 Birthday Honours and was given a knighthood.
