On his first visit to the north as Prime Minister, Mr Johnson will pledge to do “everything in my power” to restore the power-sharing executive in Belfast, which has been suspended since January 2017 over differences between the DUP and Sinn Fein.
But his mission is set to be overshadowed by the growing stalemate between Mr Johnson’s administration and the Irish Republic, following a clash with Taoiseach Leo Varadkar over the backstop in their first phone call.
Mr Johnson told the Irish prime minister that he will approach Brexit negotiations in “a spirit of friendship” but reiterated that any fresh deal must see the backstop abolished, Downing Street said.
But Mr Varadkar told him that the emergency measure to prevent a hard border on the island was “necessary as a consequence” of UK decisions, the Irish Government said.
Yesterday’s call came after the pound fell to a two-year low as Mr Johnson’s new government hardened its tone over the likelihood of a no-deal. Their first discussion, nearly a week since Mr Johnson became PM, also came after allegations that the PM was snubbing the Taoiseach.
Number 10’s account of the call said Mr Johnson warned that the UK will be leaving the European Union by the 31 October deadline “no matter what”.
But Mr Johnson reaffirmed his commitment to upholding the Good Friday Agreement and to “never put” physical checks or infrastructure on the border, according to a spokeswoman.
“The Prime Minister made clear that the government will approach any negotiations which take place with determination and energy, and in a spirit of friendship, and that his clear preference is to leave the EU with a deal, but it must be one that abolishes the backstop,” she added.
Dublin said Mr Varadkar reiterated the EU position that Theresa May’s Withdrawal Agreement would not be renegotiated.
“On Brexit, the Taoiseach emphasised to the Prime Minister that the backstop was necessary as a consequence of decisions taken in the UK and by the UK Government,” a spokesman said.
“Alternative arrangements could replace the backstop in the future, as envisaged in the Withdrawal Agreement and the Political Declaration on the future relationship, but thus far satisfactory options have yet to be identified and demonstrated.”
The Taoiseach also invited Mr Johnson to Dublin to “further their respective analyses on Brexit”, Ireland said.
But the PM has so far refused to sit down with EU leaders until they agree to renegotiate the Withdrawal Agreement.