AFTER a remarkable career spanning five decades, DUP leader Ian Paisley last night announced he is to stand down as party chief and First Minister of Northern Ireland.

The announcement, which followed weeks of intensifying speculation, represents a huge moment in the politics and recent history of Northern Ireland, removing from the scene one its most striking figures.

His decision came just nine months after leading his party into a power-sharing agreement with Sinn Fein -- a move for long regarded as inconceivable for the firebrand, once best known for bellowing his catch-cry of "Ulster Says No".

But political leaders last night agreed the man famous for saying 'No' will now go down in history for saying 'Yes'.

Dr Paisley gave in to mounting pressure from within his own party in recent weeks to stand aside.

The decision of the 81-year-old to resign cast a minor doubt over the DUPs power-sharing arrangement with Sinn Fein.

But Government sources believe the DUP will remain in the Northern Ireland executive, although with a possibly cooler relationship with Sinn Fein.

Dr Paisley will quit politics after an investment conference in Belfast in May organised by the Stormont power-sharing Executive.

However, he will continue as an MP in Westminster and MLA in Stormont.

The central political question now is who will take over from Mr Paisley at the head of the party which he founded more than three decades ago. Successor

The political world expects his successor to be Peter Robinson, his deputy for decades who is currently finance minister in Belfast's powersharing executive.

His experience and reputation for efficiency may mean he will face little serious opposition for the two top jobs now becoming vacant. A smooth transition and a Robinson promotion would suit most of the political spectrum, including the British and Irish governments and Sinn Fein.

Tributes to Dr Paisley were led by Taoiseach Bertie Ahern and British Prime Minister Gordon Brown.

Watershed

Mr Ahern, who writes for this paper today on his long association with the DUP leader, also said last night that the announcement was "a watershed in the history of Ireland". He described Dr Paisley as "a giant figure in the history of these islands".

The Taoiseach said his contribution would sit with Carson and Craig in the annals of unionist politics.

"In recent years, I have grown to know Dr Paisley and have valued the practical and friendly working relationship that developed between us," Mr Ahern said.

"I respect him as a man who worked tirelessly for the people he represents and who has sincerely done what he believed was right.

"In time, history will come to a fuller judgment of the many aspects of his long career."

British Prime Minister Gordon Brown said Dr Paisley had made a huge contribution to political life.

"Progress on bringing a lasting peace to Northern Ireland would not have been possible without his immense courage and leadership," he said.

Former British prime minister Tony Blair also praised Mr Paisley's "decisive'' contribution to the peace process.

"In short, in the final analysis, he made it happen. The man famous for saying 'No' will go down in history for saying 'yes'," he said.

Dr Paisley refused to endorse a successor as he denied his departure had anything to do with his son's controversial resignation last week.

He enjoyed a publicly cordial relationship with his Deputy First Minister, Sinn Fein's Martin McGuinness, which led the unlikely pair to become known as the 'Chuckle Brothers'. But the relationship also caused unease within his own party. Dr Paisley's successor is expected to be his second-in-command, Peter Robinson, who is the Northern finance minister.

But Nigel Dodds, the Enterprise Minister, cannot be ruled out of the equation if he decides to run.

In typical quick-witted form, Dr Paisley, last night refused to be drawn on who would succeed him.

"This is not the church of Rome,'' he said on UTV.

He said his successor will have his support and encouragement.

Sinn Fein president Gerry Adams said he wanted to commend the positive contribution he made in recent times.

Mr Adams said there was no reason for instability when the leadership changes.

The clamour inside the party for Dr Paisley to stand aside for the next generation of DUP leaders grew after the announcement last Friday that his son, Ian Paisley jnr, has been appointed to the Policing Board, following his resignation as a junior minister.

Mr Paisley jnr was forced to resign from the Stormont Executive over his links to a property developer.

- Fionnan Sheahan Political Editor