Full statement from Ulster Unionist leader David Trimble on his resignation.
"At a private meeting with the president and chairman of the Ulster Unionist Party this morning, I indicated to them that I do not wish to continue as leader.
"I want to thank all the members of the party for all the support and help they have given me over the last 10 years.
"There have been difficult times, but also times when we have been able to make a difference.
"I have no doubt that Northern Ireland is a much better place and unionism
greatly advantaged because of our efforts.
"I am pleased to have had the privilege of leading of what I regard as the best and most democratic political grouping in Ulster.
"The party chairman will be arranging for a meeting of the party executive to make the arrangements for a special meeting of the Ulster Unionist Council to elect a new leader, at which point I shall formally resign."
Full statement from Prime Minister Tony Blair responding to the resignation news.
"History will show that without David Trimble's period as leader of the Ulster Unionist Party, Northern Ireland could never have become the changed place it is today.
"Throughout he showed real leadership - vision, courage and a sheer dogged determination despite all the difficulties involved in the search for peace.
"Without him, there would have been no Belfast Agreement. It would not have been possible to bridge the deep divide in Northern Ireland.
"But David showed the courage to reach out and respond to nationalists and republicans, at the same time as safeguarding the interests of his own community.
"And throughout the protracted process of implementing the Agreement David has stuck to those two key principles.
"He did so knowing the political risks he was running, but did so because he believed it was for the greater good of the whole community in Northern Ireland.
"As a result people's lives are not only better, but the tragic litany of death and destruction that cast a pall over so many years is now receding into the past.
"Unfortunately the peace process is not yet complete, but the efforts David has made, and the price he has paid, places a responsibility on all of us to finish the job."