Lord Trimble led the Ulster Unionist Party (UUP) between 1995 and 2005, and was instrumental in the peace deal which ended the worst of Northern Ireland's Troubles.
In a statement on behalf of the Trimble family, the UUP said: “It is with great sadness that the family of Lord Trimble announce that he passed away peacefully earlier today following a short illness.”
One of the principal architects of the Belfast Agreement ending decades of conflict in Northern Ireland has died at the age of 77.
Lord Trimble jointly won the Nobel Peace Prize along with SDLP leader John Hume.
Brandon Lewis, who resigned as Northern Ireland Secretary earlier this month, tweeted: “Incredibly sad news that David Trimble has died.
"A brilliant statesman and dedicated public servant, his legacy as an architect of the Good Friday Agreement will live on forever.
"The people of the UK owe him an immense debt of gratitude for all he achieved for our Union.”
Lord Trimble has died at the age of 77
PA
Lord Trimble with former Prime Minister David Cameron
Stefan Rousseau
Labour leader Sir Keir Starmer added: “Very sad news. David Trimble was a towering figure of Northern Ireland and British politics as one of the key authors of the Good Friday Agreement, the first First Minister and winner of the Nobel Peace Prize.
"My thoughts are with Lady Trimble and their family.”
The Co Down man distinguished himself in an academic career in the law faculty at the Queen’s University Belfast before moving into politics.
He initially became involved in the unionist offshoot organisation Vanguard in the early 1970s and while he was best known for his involvement with the Belfast Agreement, in his younger days he had opposed an earlier attempt, the Sunningdale Agreement.
He went on to join the then dominant Ulster Unionist Party in 1978.
It was at the university in 1983 that he heard the IRA’s gunshots which killed his fellow law professor and UUP colleague Edgar Graham and later identified the body.
He left academia for politics full time when he was elected as MP for Upper Bann following a by-election in 1990 after the death of the incumbent Harold McCusker.
Lord Trimble rose to prominence partly due to the Drumcree dispute as nationalist residents opposed the procession of an orange parade along the Garvaghy Road.
He led the parade along the road in 1995, famously joining hands with Democratic Unionist leader Ian Paisley.
A few months later, Lord Trimble unexpectedly won the leadership of the Ulster Unionist Party over the favourite Lord Kilclooney, starting his often turbulent time at the helm of the party.
He marked a number of firsts as Ulster Unionist leader, including becoming the party’s first leader in 30 years to meet with the Irish premier in Dublin and in 1997 he became the first unionist leader since partition to negotiate with Sinn Fein.
The peace talks, which started formally in 1998 under the chairmanship of former US senator George Mitchell, saw many nights of intensive negotiation pressed on by then prime minister Tony Blair, taoiseach Bertie Ahern and then US president Bill Clinton.
The process faltered several times but perhaps most notably when then Ulster Unionist Jeffrey Donaldson walked out of the talks.
But on April 10, 1998 the agreement was signed, and endorsed following a referendum held the following month.
Lord Trimble become the first first minister of Northern Ireland to be elected on July 1, 1998 alongside SDLP deputy leader Seamus Mallon as deputy First Minister.
But the path of devolved government was far from smooth for the two men, with the issue of the paramilitary groups decommissioning overshadowing Stormont.
Lord Trimble also struggled with internal divisions within his party which saw Mr Donaldson, along with fellow future DUP leader Arlene Foster and Norah Beare, resigning in December 2003.
Lord Trimble lost his Westminster seat in Upper Bann at the 2005 election to DUP candidate David Simpson.
He resigned as leader of the party whose once dominant Westminster representation had been reduced to just one seat.
He was made a life peer the following year and later took up his seat in the House of Lords as a member of the Conservative Party to have, he said, great influence on UK politics.
While generally socially conservative in outlook, Lord Trimble admitted in July 2019 that he had changed his position on equal marriage after his daughter Victoria married her girlfriend in 2017.
Lord Trimble’s final public appearance came at the end of June at the unveiling of a portrait of him by artist Colin Davidson at the Queen’s University.
He then reflected on the approach of the 25th anniversary of the Belfast Agreement, and pointed out it has survived despite the objections.
He was also sharply critical of the UK Government over Brexit trade arrangements.
Lord Trimble is survived by his wife Daphne and sons and daughters, Richard, Victoria, Nicholas and Sarah.
Lord Trimble was a key figure in the Northern Ireland peace process
Haydn West
Lord Trimble meeting the Queen
Fiona Hanson
Lord Trimble with former Prime Minister Tony Blair
Tim Ockenden
Lord Trimble with Prime Minister Boris Johnson
PA
