Sir Jeffrey Donaldson has said David Trimble was a “titan of unionism” despite their political differences.
The DUP leader also said that all unionists must recognise that consensus politics and powersharing, as supported by Lord Trimble, is the way forward for Northern Ireland.
Lord Trimble, who was instrumental in the negotiation of the 1998 Good Friday/Belfast Agreement, died on Monday aged 77.
Sir Jeffrey quit the Ulster Unionist Party in 2003 and defected to the DUP after he disagreed with his then party leader over the agreement and IRA decommissioning.
You can differ with someone but admire their courage and determination and their commitment to what they believe in— Sir Jeffrey Donaldson
But he told the BBC Good Morning Ulster programme: “There is no doubt that David was a titan of unionism.
“He was someone who believed passionately in the union and I have to say that despite our differences in the latter years when I was in the Ulster Unionist Party, he was someone I got on very well with.
“I worked closely with him. He worked enormously hard, he believed strongly in what he was doing and he wanted to build a better future for everyone in Northern Ireland.”
Sir Jeffrey said he never doubted Lord Trimble’s commitment to making Northern Ireland work.
“Despite our differences, David’s objective was to deliver political stability in Northern Ireland and he believed in doing so to preserve and protect the union.
“You can differ with someone but admire their courage and determination and their commitment to what they believe in.
“In David I saw someone who was courageous as a leader, who was determined to pursue the path he had chosen.
“Leadership is difficult, I suppose I am discovering that at the moment. At times it can be quite a lonely path.
“When I look at David I never doubted his commitment to the union, his commitment to Northern Ireland, his commitment to making this place work.”
He added: “Our differences were not on the overall strategic approach, they were on the tactics and the approach that was taken, particularly on the question of (IRA) decommissioning and of getting to a place where we had politics without guns in Northern Ireland.
“What we have is imperfect and we must keep building on it and trying to get stronger and firmer foundations for what we have in Northern Ireland.
“But David fundamentally recognised that the way forward was through consensus, it was through powersharing, built upon that cross-community consensus.
“That remains my view and unionism must recognise that is the path and the way forward. I think the vast majority of unionists do accept that the way forward is through consensus.
“In the end, a Northern Ireland that is at peace with itself is a Northern Ireland in which the union will flourish.”
Former UUP deputy Lord Kilclooney said that Lord Trimble realised that the Good Friday Agreement was positive for Northern Ireland even in the face of opposition from some unionists.
He told the BBC: “We were disappointed that some people who were with us walked away but he realised that what he was doing was good for Northern Ireland.
“You can’t bring them all with you.”
Former Alliance Party leader and Stormont Assembly speaker, Lord Alderdice, said Lord Trimble took “extraordinary risks” to help deliver the agreement.
He said: “Courage isn’t in standing against your opponents, it is in standing against people from your own part of the community when you know that something different has to be done for the wellbeing of everyone.
“There are many politicians who stick their finger up in the air and see what way the wind is blowing.
“David Trimble wasn’t like that, he tried to work out what was right and what was good and what was the best thing to do for Northern Ireland, for his community, even if it involved risk and sacrifice on his own part.
“Present and future generations in politics and beyond will continue to owe him far more than they ever know.”
Lord Alderdice added: “In terms of politics, David Trimble took extraordinary risks with great courage and stuck with it and history will judge him kindly because of that.”