Outgoing Ulster Unionist leader Sir Reg Empey today formally confirmed he will step down as the party's figurehead next month.
His resignation was already on the cards after a disappointing General Election, but party chairman David Campbell said Sir Reg had now officially confirmed his decision to resign on September 22.
The announcement means the race for his successor can begin in earnest.
Sir Reg took leadership of the party in 2005 with the intent of challenging the growing power of the Democratic Unionist Party, but a ground-breaking electoral alliance with David Cameron's Conservatives failed to excite voters. The once-mighty Ulster Unionist Party ended the recent General Election campaign without a single MP.
But Mr Campbell today praised Sir Reg's contribution to the party, saying: "His period of leadership of our party has produced the reform and modernisation of our structures which eluded his predecessors and he has restored financial stability to our organisation and undoubtedly moved the UUP and Northern Ireland closer to mainstream British political life."
Sir Reg will continue to carry out the functions of leader until a replacement is elected at a meeting of party members planned for Belfast's Waterfront Hall on September 22.
Mr Campbell said nominations were now open in the race to find a successor to Sir Reg.
The current favourite is Fermanagh-South Tyrone Assembly member Tom Elliott. The rural representative is a leading Orange Order member and has already received the backing of a number of senior figures in the party.
Mr Elliott is likely to favour closer cooperation with the Democratic Unionists, having been one of the chief architects of the deal to agree a joint unionist candidate in his own constituency in the General Election, though the move failed to unseat the sitting Sinn Fein MP.
He is expected, however, to face a challenge from Basil McCrea from the Lagan Valley constituency close to Belfast.
Though a fairly recent addition to Ulster Unionist ranks at the Assembly, he has secured a high profile and is a member of the Northern Ireland Policing Board which oversees the policing service.
Though ranked as an outsider, he is seen as a would-be moderniser of the party.
Nominations for the leadership contest close on August 31.
Sir Reg took over leadership of the party from David Trimble.
In the late 1990s both senior unionists were at the forefront of all-party negotiations which led to the Good Friday Agreement in 1998.
The Democratic Unionist Party (DUP) opposed the pact which saw the SDLP and Sinn Fein take seats in a power-sharing government and accused their unionist rivals of caving in to the pressure for a deal.
By 2005 Sir Reg took leadership of a party which was losing political strength to the Democratic Unionists.
The DUP later entered its own negotiations with the British and Irish governments, with Sinn Fein, and the resulting St Andrews Agreement saw the parties enter a shared administration at Stormont.
Sir Reg serves as minister at the Department for Employment and Learning (DEL) in the government led by Sinn Fein and the Democratic Unionists. He had earlier served as minister at the Department of Enterprise, Trade and Investment (DETI) in an earlier administration.
Mr Campbell said: "I wish to place on record my personal thanks, and that of the entire party, for the leadership of our party and our community that Sir Reg has undertaken over many years.
"As the party's chief negotiator during the all-party talks he negotiated the settlement that has led to the peace and stable devolved government that is enjoyed today.
"As a minister at DETI and then at DEL he has been forward in protecting and promoting our economy both at home and abroad, and has always been a constructive partner in the Northern Ireland Executive."