Mike Nesbitt confirmed as UUP leader
Mr Nesbitt returns to the role for the second time
The new leader of the UUP has warned that Stormont will "be gone for good" if powersharing collapses again.
Mike Nesbitt told his party conference "it's good to be back" as he returned as leader for the second time.
In his speech on Saturday, Mr Nesbitt sought to strike a tone of hope, unity and co-operation across the region and neighbouring governments.
However, he also cautioned that the people of Northern Ireland "must learn how better to rub along together" and protect devolution.
"It is my firm view that if Stormont collapses again, it is gone for good," he said.
"Any new agreement would require a negotiation on the scale of 1998 and, frankly, I doubt if that could be done in the modern age, where social media and alternative truths are so disruptive.
"Devolution is a precious asset. We should do all we can to protect it and allow it to thrive. "
Mr Nesbitt used the speech, which officially marked his return as leader, to set out a vision of "relaxed, confident and inclusive unionism" for the party.
"It's good to be back. Be in no doubt, I'm determined to do a job for this party and the success of that job will be measured by the degree it works for the benefit of all the people of Northern Ireland - and our neighbours in England, Scotland, Wales and the Republic of Ireland."
However, celebrations were somewhat dampened as he was forced to deliver his leader's speech remotely after contracting Covid-19.
The UUP had been confident that Mr Nesbitt, who is also Stormont's health minister, would be able to attend the event on Saturday after missing several days of Stormont business this week.
However, on Friday it was confirmed that he had not recovered sufficiently to personally attend the conference at the Crowne Plaza in Belfast.
It was announced last month that Mr Nesbitt, 67, was to become UUP leader for the second time - having held the post between 2012 and 2017.
He was the only declared candidate for the position following the resignation of Doug Beattie.
Mr Nesbitt paid tribute to the former leader, although he said he did not want to "dwell on the whys and wherefores" of his ousting from the role.
"Thank you, Doug. I hope we can continue to support each other and enjoy each other's company," he said.
In comments delivered remotely to screens at the conference, he called on the memory of another party leader, the late David Trimble, and expressed a wish to leave behind "a dark sludge of historical sectarianism".
Saying he wanted to campaign around the single word of "hope", the Strangford MLA also dedicated time in his speech to address "unionist cooperation".
Noting that unionist parties differed on vision and strategy on securing Northern Ireland's place in the UK, he said the UUP would follow a course of action dictated by common sense - including "practical co-operation with the Republic of Ireland".
He warned against confusing "compromise with appeasement", and allowing views to become fixed, inflexible and "lodged in ideological cement".
"We need to continue to learn to live together, for mutual advantage," he said.
The former victims and survivors commissioner also appeared to criticise the decision-making of the UK Government following the announcement of a public inquiry into the 1989 murder of Pat Finucane.
He said the decision "demonstrates how uneven is the approach to truth and justice".
He added: "I sincerely hope the Finucane family find out what they need to know about the dreadful murder of Pat Finucane - just as I hope every victim and survivor gets truth and acknowledgement - even if truth and justice are beyond them.
"But the decision once again perpetuates the idea of a hierarchy of victims. As a former victims commissioner, I have often challenged MPs and indeed Cabinet ministers in these terms.
"Would you look two of your own constituents in the eye and tell one they could have a public inquiry into their loved one's death but deny it to the other? It is not fair. It is not equitable. It's not right."
In a reference to Charles Dickens' Memorable Day, Mr Nesbitt said the legacy of the Troubles is a multigenerational "story of thousands upon thousands of our people being wrapped in chains of thorns".
Addressing his own future, Mr Nesbitt said it was his preference that UUP councillor Richard Smart would succeed him in his role as Strangford MLA but added: "He'll have to wait a while yet."