Sinn Féin vice president Michelle O’Neill called on political parties in Northern Ireland to unite to “stand up to the Tories”, following the resignation of Prime Minister Liz Truss.
She tweeted: “The chaos & disastrous policies of the Tories has heaped misery onto workers & families.
“Liz Truss joins the long line of British Prime Ministers who have failed people.
“We need all parties in the North to work together, stand up to the Tories & support people in a new Executive.”
Ms Truss announced her resignation after a chaotic 44 days in office during which she lost the confidence of Tory MPs and the public and oversaw economic turbulence.
She is set to become the shortest serving Prime Minister in history after she battled an open revolt from Conservatives demanding her departure.
Speaking from a lectern in Downing Street, Ms Truss said she had told the King she was resigning as the leader of the Conservative Party as she recognised she “cannot deliver the mandate” which Tory members gave her little over six weeks ago.
She held talks with the chairman of the 1922 Committee of backbench Conservatives Sir Graham Brady and agreed to a fresh leadership election “to be completed within the next week”.
“This will ensure that we remain on a path to deliver our fiscal plan and maintain our country’s economic stability and national security,” she added, as she was accompanied by husband Hugh O’Leary.
“I will remain as Prime Minister until a successor has been chosen.”
Read more:Taoiseach asks for Liz Truss's successor to be selected quickly
Sir Graham Brady, chairman of the Tory 1922 Committee, said he expected the new leader to be in place by Friday, October 28.
He told reporters: “I have spoken to the party chairman Jake Berry and he has confirmed that it will be possible to conduct a ballot and conclude a leadership election by Friday the 28th of October.
“So we should have a new leader in place before the fiscal statement which will take place on the 31st.”
Mr Brady said he expects Tory members to be involved in choosing a new party leader.
Asked if the party faithful will be included in the process, he told reporters: “Well, that is the expectation.
“So the reason I’ve spoken to the party chairman and I discussed the parameters of a process is to look at how we can make the whole thing happen, including the party being consulted, by Friday next week.”
Sir Graham added: “I think we’re deeply conscious of the imperative in the national interest of resolving this clearly and quickly.”
Labour leader Sir Keir Starmer demanded a general election “now” so that the nation can have “a chance at a fresh start”.
Without a general election, the Conservatives will be on their third prime minister on the mandate won by Boris Johnson in December 2019.
Sir Keir said: “The Conservative Party has shown it no longer has a mandate to govern.
“The British public deserve a proper say on the country’s future. They must have the chance to compare the Tories’ chaos with Labour’s plans to sort out their mess, grow the economy for working people and rebuild the country for a fairer, greener future.
“We must have a chance at a fresh start. We need a general election – now.”
The pound has lifted on the announcement.
Sterling shot up to 1.13 US dollars before the speech as markets anticipated that Ms Truss would resign, before paring back gains slightly to stand 0.4% higher at 1.126 US dollars after her resignation statement.
Taoiseach Micheál Martin issued his best wishes to Ms Truss upon her resignation and said that a resolution to the Northern Ireland Protocol dispute was now "ever more urgent".
He said: "I had a number of opportunities to engage with Prime Minister Liz Truss during her brief period as prime minister and I convey my best wishes to her and her family, following today's announcement of her resignation.
"Working together to protect the gains of the Good Friday Agreement and to support peace and stability in Northern Ireland continue to be vital responsibilities for the British and Irish governments, particularly now in the absence of a functioning Northern Ireland Executive and Assembly.
"Substantive EU-UK engagement to reach agreement on outstanding issues around implementation of the Protocol is ever more urgent.
"Britain is Ireland's closest neighbour and a relationship of partnership between the British and Irish governments is vital for peace and prosperity on these islands. I remain committed to working with the British government in this spirit."
Former Taoiseach Bertie Ahern was critical of Liz Truss, describing her stance on the Northern Ireland Protocol negotiations as unhelpful.
'A disaster from start to finish'
Alliance leader Naomi Long said Liz Truss’s term as prime minister "was a disaster from start to finish and will go down in history for all the wrong reasons”.
“It had degenerated into a disaster a day, sometimes an hour, for Liz Truss, driven by her decision to pursue a hard right agenda, including trickle down economics, which sent the economy into meltdown and compounded the pain of families and businesses already under strain as a result of the cost of living crisis.
“This relentless chaos has yet again underlined the urgency of restoration of a functioning and reformed Stormont Executive. In previous crises we have been able to fall back on Westminster intervention. However, we do not have that luxury given the unprecedented scale of the crisis unfolding in Westminster.
“While an Assembly and Executive cannot fix international or national crises, they can provide leadership for local people during this unprecedented time and help guide our public services and finances through this difficult period.
“Whatever the outcome in Westminster of this latest development, our priority and our duty to people here is to get back to work ahead of next week's deadline and deliver the best leadership we can for their sake.”
UUP leader Doug Beattie said the new prime minister "needs to devote some time to restoring devolved government in Northern Ireland".
“Back in July as Boris Johnson was preparing to leave office, I said that the United Kingdom needs strong, stable Government and that this was especially the case with regard to Northern Ireland in the absence of the devolved institutions.
“Three months on, another Prime Minister is about to depart and nothing has changed. If anything the situation is even worse in terms of the cost of living crisis and uncertainty caused by the Northern Ireland Protocol.
“Whoever emerges as Prime Minister, he or she needs to devote some time to restoring devolved Government in Northern Ireland and reverse the damage done to the Belfast Agreement by the NI Protocol. That will not be facilitated by an Assembly Election - at the cost of £6.5M - a mere five months after the last one, because such an Election will not resolve the issues around the Protocol.
“I would therefore urge the present prime minister to act now to ensure that an Assembly Election is not called until a new prime minister is in place; a new Secretary of State for Northern Ireland appointed and that the new Secretary of State has time to engage with the political parties in order to work in the best interests of Northern Ireland.”
'US and UK are strong allies'
US president Joe Biden said in a statement: “The United States and the United Kingdom are strong Allies and enduring friends — and that fact will never change.
“I thank Prime Minister Liz Truss for her partnership on a range of issues including holding Russia accountable for its war against Ukraine.
“We will continue our close cooperation with the U.K. government as we work together to meet the global challenges our nations face.”
Tony Danker, director-general of the CBI, said: “The politics of recent weeks have undermined the confidence of people, businesses, markets and global investors in Britain. That must now come to an end if we are to avoid yet more harm to households and firms.
“Stability is key. The next prime minister will need to act to restore confidence from day one.
“They will need to deliver a credible fiscal plan for the medium term as soon as possible, and a plan for the long-term growth of our economy.”
Yields on gilts – UK government bonds – have eased slightly in response to Prime Minister Liz Truss’s decision to resign.
UK 30-year gilt yields, which fall as price improve, fell back by 0.44% to 3.86% on Thursday.
Yields had dropped even further shortly before the Prime Minister’s statement at 1.30pm but sprang back slightly.
Ms Truss’s resignation came just a little over 24 hours after she told MPs she was “a fighter, not a quitter”.
But her odds of survival were slashed after chaotic scenes in the Commons followed the resignation of Suella Braverman as home secretary.
The number of Tory MPs publicly demanding Ms Truss’s resignation doubled before lunch was over on Thursday, taking the total to 15, but a far greater number were privately agitating for her exit.
Ms Truss will still have to meet the King in person to formally tender her resignation, as is tradition.
This will take place immediately before the monarch asks her successor, also in person, to form a government.
