UPDATE: Theresa May to become Prime Minister on Wednesday, David Cameron has confirmed, after another day of high drama in British politics.
Labour and the Liberal Democrats have called for a snap general election after Andrea Leadsom unexpectedly dropped out of the Conservative leadership race, leaving Theresa May as the sole contender to become the next UK prime minister. Jon Trickett, Labour's election co-ordinator, argued it was crucial for Britain to have a "democratically elected" leader.
"It now looks likely that we are about to have the coronation of a new Conservative Prime Minister," he said. "It is crucial, given the instability caused by the Brexit vote, that the country has a democratically elected prime minister.
"I am now putting the whole of the party on a general election footing. It is time for the Labour Party to unite and ensure the millions of people in the country left behind by the Tories' failed economic policies, have the opportunity to elect a Labour government."
Tim Farron, the Liberal Democrat leader, made a similar case. "Just 13 months after the last election the Conservatives have plunged the UK into chaos. It is simply inconceivable that Theresa May should be crowned prime minister without even having won an election in her own party, let alone the country," he declared.
"There must be an election. The Conservatives must not be allowed to ignore the electorate, their mandate is shattered and lies in ruins. Britain deserves better than this Tory stitch-up.
"May has not set out an agenda, and has no right to govern. She has not won an election and the public must have their say."
But the home secretary has previously ruled out an early general election. "There should be no general election until 2020," May said on 30 June. "There should be a normal autumn statement held in the normal way at the normal time and no emergency budget."
The Remain campaigner at the EU referendum also stressed that "Brexit means Brexit" after the UK vote to leave the 28-nation-bloc. However, May said she would not immediately trigger Article 50 of the Lisbon Treaty, the mechanism which signals the UK's intention to leave the EU, until a clear negotiating plan is outlined.
The 1922 Committee chair, Graham Brady, will now meet with the Conservative Party's board to discuss whether May will be appointed as David Cameron's successor. The contest was originally planned to go to vote of the 150,000 Tory party members.
A general election may prove tricky for Labour, which faces a leadership contest after Angela Eagle launched her challenge against Jeremy Corbyn today. The former shadow business secretary had urged Corbyn to resign after a vast majority of Labour MPs backed a confidence of "no confidence" against him.
But the left-winger has vowed to stay on, with Labour general secretary Iain McNicol asking the chair of the party's National Executive Committee to convene a meeting to set the election rules.
Corbyn secured almost 60% of the vote in the 2015 contest and has the support of the trade unions, including Unison and Unite, but he may have to attract 51 nominations from MPs and MEPs to get on the ballot.