Boris Johnson has insisted a dinner with the DUP has not undermined his impartiality in efforts to restore Stormont powersharing.
The Prime Minister dined with DUP leader Arlene Foster and other senior party colleagues in Belfast on Tuesday.
The event came amid ongoing negotiations aimed at renewing the Conservatives’ confidence and supply deal with the unionist party which is keeping Mr Johnson’s minority Government in power.
The dinner in Belfast was organised ahead of Mr Johnson’s first visit to Stormont as Prime Minister, where he is holding a series of meetings with the five main parties on Wednesday morning.
Critics have claimed the Government is unable to act as an impartial mediator in talks to restore the crisis-hit institutions due to the controversial Westminster deal with the DUP.
Mr Johnson denied a conflict of interest as he arrived at Stormont House on Wednesday.
“It’s all there in the Good Friday Agreement, we believe in complete impartiality and that’s what we are going to observe,” he said.
“But the crucial thing is to get this Stormont government up and running again.”
Earlier, Mrs Foster maintained the confidence and supply deal had not been the focus of the dinner.
Sinn Fein President Mary Lou McDonald was critical of the dinner, challenging Mr Johnson to stop being the DUP’s “gopher”.
Mr Johnson said he was in Northern Ireland to concentrate on the devolution impasse.
“It’s great to be here in Northern Ireland,” he said.
“Clearly the people in Northern Ireland have been without a government, without Stormont, for two years and six months, so my prime focus this morning is to do everything I can to help that get up and running again because I think that’s profoundly in the interests of people here, of all the citizens here in Northern Ireland.”
On Brexit, Mr Johnson said: “The crucial thing to stress is, I obviously attach huge importance to the letter, spirit of the Belfast Good Friday Agreement and will be insisting on that.”
Northern Ireland has been without a devolved government since early 2017, with hamstrung civil servants currently running under-pressure public services amid a reluctance by the Government to re-introduce direct rule.
Stormont’s two main parties – the DUP and Sinn Fein – remain at loggerheads over a series of long-standing disputes, with a series of talks initiatives aimed at securing a resolution having ended in failure.
Mr Johnson’s visit to Stormont comes amid deadlock in the latest talks process.
Workers from the under-threat shipyard Harland and Wolff; anti-Brexit campaigners; Irish language activists; and families of people killed by the security forces during the Troubles were among those holding protests at Stormont on Wednesday to mark Mr Johnson’s visit.
DUP leader Mrs Foster, deputy leader Nigel Dodds and party whip Sir Jeffrey Donaldson attended Tuesday’s dinner with the Prime Minister.
The DUP’s 10 MPs have propped up the minority Government since the 2017 general election – an arrangement that delivered a £1 billion boost in public spending in Northern Ireland.
New Northern Ireland Secretary Julian Smith did not attend the dinner, although he was at Stormont House on Wednesday morning to greet Mr Johnson.
On Wednesday morning, Mrs Foster told the BBC that three main issues were discussed over dinner with Mr Johnson: the restoration of devolved government, Brexit and strengthening the union.
Asked whether negotiations were taking place on the confidence and supply deal, she said: “The confidence and supply agreement is between the Conservative Party and the Democratic Unionist Party, it’s not just between individuals, so that confidence and supply agreement continues.
“We will of course review that confidence and supply agreement to see how it has been implemented and whether we need to make changes to it at the end of this parliamentary term and that’s what we will do then.”
Mrs Foster suggested more money could be involved in the next round of talks: “We will be focusing on what the needs of the people are when we come to talk to the Prime Minister about the next confidence and supply agreement and that’s what our focus will be.”
After their meeting with the Prime Minister, Sinn Fein’s Mrs McDonald said his stated claim of impartiality was “laughable”.
“He tells us he will act with absolute impartiality, we have told him that nobody believes that,” she said.
“Nobody believes that because there are no grounds to believe there is any kind of impartiality, much less strict impartiality.”
The republican leader said the confidence and supply deal had “poisoned the groundwater” at Stormont.
“He asked for our advice and we have strongly advised him that to make progress here he needs to ensure that he is not the DUP’s gopher, he needs to stop mollycoddling them, he needs to spell out the realities of life to them and put pressure on his unionist colleagues to ensure we can land on an equitable and sustainable agreement,” she said.
The last DUP/Sinn Fein-led powersharing coalition imploded in January 2017 when the late Martin McGuinness quit as Sinn Fein deputy first minister amid a row about a botched green energy scheme.
The fallout over the Renewable Heat Incentive (RHI) was soon overtaken by disputes over the Irish language, same-sex marriage and the toxic legacy of the Troubles.