Boris Johnson told no-deal Brexit planning must include Irish border poll
Sinn Fein challenge the PM "very strongly" on his EU exit plans and say they must include preparations for a unity referendum.
Boris Johnson's first visit to Northern Ireland as prime minister has concluded in a stand-off over an Irish border poll.
Mr Johnson sat down on Wednesday with the five Northern Ireland parties attempting to reach agreement in a new power-sharing deal at Stormont.
During the talks, the prime minister repeated his pledge that the UK will be leaving the EU in 92 days' time "come what may", despite his "intention to do so with a deal", Downing Street revealed.
David Frost, Mr Johnson's Europe adviser, will be dispatched to Brussels in the coming days for introductory meetings with key EU officials.
He will pass on the prime minister's message that the UK will "work
energetically" for a Brexit deal, but any agreement must see the
controversial Irish border backstop arrangement "abolished", a UK
spokesperson said.Mr Johnson sat down on Wednesday with the five Northern Ireland parties attempting to reach agreement in a new power-sharing deal at Stormont.
During the talks, the prime minister repeated his pledge that the UK will be leaving the EU in 92 days' time "come what may", despite his "intention to do so with a deal", Downing Street revealed.
David Frost, Mr Johnson's Europe adviser, will be dispatched to Brussels in the coming days for introductory meetings with key EU officials.
Following discussions with Mr Johnson, Sinn Fein leader Mary Lou McDonald revealed her party had challenged Mr Johnson "very strongly" on his promise to take the UK out of the EU on 31 October, with or without a divorce deal.
She also repeated her demand for a public poll on Irish reunification in the event of a no-deal Brexit.
"We've set out very clearly that this will be catastrophic for the Irish economy, for Irish livelihoods, for our society, for our politics and for our peace accord," Ms McDonald said.
"We've made it clear to him that the extensive planning that he tells us he's carrying out in respect of a potential crash Brexit has to include the constitutional question and the issue of a border poll here in Ireland.
"We've stated to him very clearly that Brexit in any event - but certainly a disorderly Brexit - represents in anybody's language a dramatic change of circumstances on this island.
"It would be unthinkable in those circumstances that people would not be given the opportunity to decide on our future together."
Ms McDonald also criticised the DUP's confidence and supply agreement with the Conservatives - which keeps the Tories in power at Westminster - for having "poisoned the groundwater" and made power-sharing negotiations "very, very, very difficult".
"Our experience, thus far, over the last number of years with the Conservative government is that they will do everything and anything to protect their own interests, they will do everything and anything to ensure they remain in government," she added.
"There is no doubt that Boris Johnson's first priority coming to Ireland is his interest, Tory interest, British interests as he sees them.
"And it seems to me he is quite complacent at the idea of Ireland being the collateral damage."
She warned Mr Johnson not to be the "DUP's gopher".
DUP leader Arlene Foster hit back, claiming Mr Johnson would be impartial in efforts to restore devolved government in Northern Ireland, but suggested he would not put the future of the UK at risk.
"The prime minister again reiterated the fact that he would never be neutral on the Union, we welcome that," she said.
"He will, of course, be neutral on the administration of government here in Northern Ireland but you shouldn't confuse the two.
"Today I've heard those two matters confused quite regularly.
"He'll never be neutral on the Union and talk of a border poll, he told us, was not something that he was entertaining."
The Central Bank of Ireland predicted on Wednesday that a no-deal Brexit could see the country's economic growth slashed from a forecast 4.5% to 0.7% next year, with the loss of 34,000 jobs by the end of 2020.
This would see Ireland go from being one of the fastest growing EU economies to one of the slowest.
Sky News' senior Ireland correspondent David Blevins described "a very noisy morning on the Stormont estate" amid growing tensions over Brexit.
"We're in very, very challenging days," he said.
"Some would suggest, perhaps, the relationship between the British and Irish governments is facing its greatest test of the peace process."
:: Listen to Sophy Ridge on Sunday on Apple podcasts, Google podcasts, Spotify, Spreaker
Mr Johnson arrived in Belfast on Tuesday night and had a private dinner with DUP leader Arlene Foster, deputy leader Nigel Dodds MP and chief whip Jeffrey Donaldson MP.
He denied the dinner would lead to questions over the UK government's impartiality in power-sharing discussions
The prime minister said: "It's all there in the Good Friday Agreement, we believe in complete impartiality and that's what we're going to observe."
On his arrival for talks at Stormont House, the prime minister said: "The people of 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 all citizens here in Northern Ireland.
"I'll be helping the parties in any way I can to help get that going and over the line."
It was January 2017 when the devolved government in Northern Ireland collapsed over a botched renewable energy scheme costing the taxpayer £400m.