Restoring powersharing in Northern Ireland is the 'right thing' to do for the future of the Union, British Prime Minister Rishi Sunak has said.
Mr Sunak urged political leaders to fulfil the promise of the Good Friday Agreement and return to devolved government as he gave the closing address at a landmark conference marking the 25th anniversary of the peace accord that largely ended the Troubles.
In recent days leaders who helped broker the agreement, including former US president Bill Clinton, have attended to speak about the legacy of the deal which helped end violence in Northern Ireland.
Speaking at the end of the three day conference at Queen's University Belfast, Mr Sunak made a direct appeal to unionists blocking the institutions.
The DUP is using a veto contained within the powersharing structures to prevent the operation of devolution in protest at post-Brexit trading arrangements the party contends has weakened Northern Ireland's place within the UK.
Mr Sunak insists the new Windsor Framework deal he recently struck with the EU had addressed the DUP concerns over sovereignty and trade.
However, the DUP remains unconvinced by the new settlement and is urging the Government to provide more assurances.
Mr Sunak said: "I urge you to work with us to get Stormont up and running again.
"That's the right thing to do in its own terms. I'm convinced it's also the right thing to do for our union.
"Now, I'm a proud unionist. We passionately believe that Northern Ireland is stronger within the United Kingdom, and the United Kingdom is stronger with Northern Ireland within it.
"But we must also build support beyond those of us who already identify as unionists. To do that, we have to show that devolved government within the United Kingdom works for Northern Ireland.
"The fact that the institutions have been down for nine of the last 25 years should be a source of profound concern.
"Over the long term that will not bolster the cause of unionism - I believe that deeply.
"So, we need to get the institutions up and running - and keep them up and running."
The British prime minister opened his speech by acknowledging that it was "far from perfect" to be marking the anniversary at a time when Stormont is in abeyance.
"But my argument today is this - the Belfast/Good Friday Agreement remains the best and only foundation for peace and prosperity," he said.
"If we can take inspiration and instruction from the way peace was achieved 25 years ago, we can fulfil the true promise enshrined in that agreement.
"The promise of stable, devolved government, a prosperous economy, and a more united society. That's the future for Northern Ireland, we must build."
In a statement DUP leader Jeffrey Donaldson said the "damaged foundations" of devolved government must have unionist as well as nationalist support for sustainable devolved government.
"We seek to re-establish the Northern Ireland Assembly by finishing the job of fully restoring Northern Ireland's place in the United Kingdom," he said.
"We stand ready to work with the Prime Minister and his Government to ensure that stable devolution is delivered through sustainable and balanced outcomes that have solid foundations based on the support of unionists as well as nationalists.
"We must get the foundations right. Short-term fixes will lead to short-term devolution and will do a disservice to those trying to make the institutions work.
"We are in the business of finishing the job and ensuring that NI's position within the Union is not continually undermined.
"Northern Ireland will only ever move forward if we all move forward together."
Taoiseach pays tribute to 1998 political leaders
Earlier at the conference, Taoiseach Leo Varadkar paid tribute to the political leaders of 1998.
"They were architects of that better future and, on behalf of all of us, I pay tribute to them for what they achieved," he said.
"I thank them from the bottom of my heart, on behalf of my generation."
The Good Friday Agreement "challenged our assumptions of what we once thought possible", Mr Varadkar said.
The Taoiseach said the difficult compromises required were seen as "political impossibilities for many", but "vision, leadership and optimism triumphed".
"Leaders defied assumptions about what was possible," he said.
"They also defied those within their own communities...who would have preferred to stay mired in conflict to avoid concessions or compromises.
"They realised that to see their way to a better future, they had to reject the divisions and differences that had kept Northern Ireland in what seemed an unresolvable impasse for many decades.
"These were not easy decisions to make and some paid a high personal and political price."
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
Mr Varadkar thanked international partners for "their ongoing commitment to the Good Friday Agreement and to Northern Ireland" over the decades.
"Last week, President Biden spoke powerfully of his, and the United States', ongoing commitment to peace and reconciliation on this island and for that we are truly grateful," he said.
"Special envoy (Joe) Kennedy's presence with us today is further concrete proof of this. A reminder of the opportunities that lie ahead, if we reach together.
"A prosperous Northern Ireland benefits us all. The all-island economy has so much potential to drive growth to the advantage of everyone in Britain and Ireland."
Mr Varadkar said: "Here in Belfast today I want to re-dedicate the Irish Government to continue to work with all the parties in Northern Ireland and with our partners in London to drive the process forward to the benefit of everyone on our islands.
"Both governments have an ongoing obligation to honour and implement the agreement and that is why I am so pleased to share a stage with Prime Minister Sunak.
"The peace process has always been at its strongest when the two governments have worked hand in hand. And Northern Ireland works best when the two governments work together with an agreed strategy.
"A partnership approach - often based on difficult decisions - has been decisive in driving things forward at crucial points in the past.
"To quote the Prime Minister, 'the agreement was born of partnership together', and I believe we can make the Good Friday Agreement fulfil its promise of reconciliation and shared achievement."
Mr Varadkar said he hopes the Windsor Framework - the recent deal brokered by the UK and EU - "will play an essential role in securing additional investment in Northern Ireland, as well as offering real economic benefits to communities across Northern Ireland".
"The framework has been welcomed by the business community, which has expressed a desire to move forward and take advantage of the opportunities and certainty it offers," he added.
"A prosperous Northern Ireland is a place in which people want to live. A place that people want to make work. A place where young people will stay and return to."
The Taoiseach was applauded as he said the people of Northern Ireland deserve a functioning assembly.
"In conclusion, I believe that the Good Friday Agreement was about defying historical expectations," he said.
"We need that kind of leadership still.
"Speaking after the agreement was concluded, John Hume said that 'unionists and nationalists have at last taken the future in their hands, they have seized control of their history rather than letting history hold them in thrall'.
"It is incumbent on Northern Ireland's political leaders today to take the initiative. To see past 'the shadow of the mountain behind'.
"To seize control of their history, to seize control of their destiny, and to lead their people into the future, and we as co-guarantors of the agreement will be here to help, every step of the way."
Mr Varadkar used the occasion to meet Mr Sunak, Ms Von der Leyen and the leaders of Northern Ireland's main parties.
"Coming just one week after the visit of President Biden to Belfast, this conference highlights the achievements of the Agreement and those who helped to shape it," Mr Varadkar said.
"We can never take away from its greatest achievement - that it brought peace to our island.
"As co-guarantors of the agreement, the Irish and British governments remain steadfast in our desire to see the restoration of the institutions and the formation of an executive."
US economic envoy Joe Kennedy III said it was important that economy prosperity touched all parts of Northern Ireland.
Mr Kennedy highlighted his own home city of Boston and the contrast between thriving areas and poorer neighbourhoods.
"No country, no government, no economy, has been able to ensure that the benefits of capitalism take hold in every corner of their communities, even one that generates 23 trillion dollars per year," he said.
"Yet that is also our collective task ahead. From my backyard to yours. To ensure that the benefits of prosperity and growth touch every single soul across this great place.
"From the city centre, past the Falls and the Shankill, to the River Foyle, and through every corner of Co Down. To be deliberate, to be intentional, to be impactful.
"If there is a place on this planet that is resilient, that is capable, that is clear-eyed and scrappy enough to take on that challenge, it's the shores we stand on today because you all aren't afraid of the hard stuff.
"You have wrestled through hundreds of years of division - tribe and tradition, country and creed, pain, hurt and loss. And you are still here.
"You are building a Northern Ireland where the Troubles of the past give way to the Triumphs of tomorrow. Where children will read about history and not relive it," he added.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
Meanwhile, former US special envoy to Northern Ireland Mick Mulvaney said that local politicians and business leaders in Northern Ireland want to see power-sharing restored.
Speaking on RTÉ's Morning Ireland, he said it remains to be seen if the current political leaders in the North have the ability to provide the leadership required.
"The centre of gravity for the community seems to be to get Stormont back up and running again," he said.
"You ran for office, I continue to scratch my head that folks run for office and then don't want to serve.
"That's what politicians do. You run for office because you want to do things. I've never imagined a situation where you'd run for office saying look, elect me and I'll do absolutely nothing.
"That can't hold. So, hopefully the folks will get back to work.
"They have to get back to work in order for the Windsor Framework to be fully implementable simply because the Stormont veto won't work if there's no Stormont.
"So, there's additional benefits now that didn't even exist six weeks ago to putting Stormont back together and hopefully this conference will create the energy that might get things moving in that direction," he said.
Mr Mulvaney said the financial benefit of how Brexit will apply in Northern Ireland is "absolutely real" and a tangible thing.
He said the US is probably not ready for a US/UK trade free trade agreement just yet, but "it's going to happen".
The question is whether it happens in ten years or three, he added.
With additional reporting by PA
