Contenders to succeed Theresa May as Britain's prime minister prepared to launch their leadership campaigns on Saturday, leaving Brexit shrouded in uncertainty.
A tearful Ms May announced her resignation on Friday, leaving the Brexit process for exiting the European Union in limbo and raising the risk of Britain crashing out of the bloc in a few months.
Ms May's statement inevitably triggered the starting gun on a two-month contest to replace her.
Ms May will step down as Conservative leader on June 7 but stay on as prime minister until party members have chosen her successor, which will happen by July 20.
"I will resign as leader of the Conservative and Unionist party on Friday, seventh of June so that a successor can be chosen," Ms May said on Friday outside 10 Downing St.
With her voice breaking up with emotion, Ms May, who endured crises and humiliation in her effort to find a compromise Brexit deal that parliament could ratify, said she bore no ill will.
"I will shortly leave the job that has been the honour of my life to hold," Ms May said. "The second female prime minister, but certainly not the last.
"I do so with no ill will but with enormous and enduring gratitude to have had the opportunity to serve the country I love."
US President Donald Trump said he felt sorry for Ms May, though he has criticised the British PM repeatedly in recent months over her handling of Brexit even as she tried to establish good relations with him.
"I feel badly for Theresa. I like her very much. She is a good woman," Mr Trump told reporters on the White House lawn. "She worked very hard. She's very strong."
The US leader is scheduled to make a state visit to Britain next month and will meet with Ms May just days before she formally resigns on June 7.
Ms May, once a reluctant supporter of European Union membership, who won the top job in the turmoil that followed the 2016 Brexit vote, steps down with her central pledges - to lead the United Kingdom out of the bloc and heal its divisions - unfulfilled.
Ms May bequeaths a deeply divided country and a political elite that is deadlocked over how, when or whether to leave the EU.
She said her successor would need to find a consensus in parliament on Brexit.
Ms May's latest effort to force through her despised Brexit deal, which included giving MPs the option of holding a referendum on the agreement, proved her final undoing.
The move prompted a furious reaction from Conservatives - including cabinet members.
"I thought she deserved one last roll of the dice. But she took those dice and threw them off the table," a senior minister told The Times.
The clamour for her to stand down reached fever pitch after Andrea Leadsom - one of the cabinet's strongest Brexit backers - resigned on Wednesday from her post as the government's representative in parliament.
She became the 36th minister to quit Ms May's dismally dysfunctional government - a modern record.
In her resignation letter Ms Leadsom told the prime minister she no longer believed her approach to Brexit would deliver on the 2016 referendum result to leave the EU.
Several senior cabinet ministers reportedly then held "frank" talks with Ms May on Thursday.
Britain's EU departure date is currently fixed for October 31, although any new leader could ask for a further delay.
Conservative Party leadership contests are typically bloodthirsty affairs, with plot twists and betrayals.
Former foreign secretary Boris Johnson is the bookmakers' odds-on favourite, ahead of former Brexit secretary Dominic Raab.
Both have embraced the prospect of a no-deal Brexit.
Tory MPs will hold a series of votes to whittle the contenders down to a final two that will be put to the party's more than 100,000 members.
Former foreign secretary and gaffe-prone Brexit cheerleader Boris Johnson is the membership's favourite, but a considerable number of Conservative MPs are thought to hold serious reservations about his suitability for the top job.
He has repeatedly said Britain should not fear a so-called no-deal Brexit.
Ms May was the surprising winner in a 2016 leadership contest to replace predecessor David Cameron after he resigned in the aftermath of the Brexit referendum
Despite having campaigned to stay in the EU, she embraced the cause with the mantra "Brexit means Brexit".
However, the decision to hold a disastrous snap election in June 2017, when she lost her parliamentary majority, left her stymied.
Ms May will leave office without any significant achievements to her name - other than the bungled handling of Brexit, according to political analysts.
"She doesn't really have a legacy that she can call her own other than just having to manage what is a very difficult issue," said Simon Usherwood, from the University of Surrey's politics department.
"I think anybody in her position would have had great difficulty."
Others were more brutal in their assessment.
"It was only an impossible job because she made it one," said Tim Bale of Queen Mary University of London.
Mr Raab as well as Foreign Secretary Jeremy Hunt and Environment Secretary Michael Gove all held off from throwing their hats in the ring on Friday, but are widely expected to stand.
The next prime minister of the UK, a country of more than 66 million people, will be decided by the 100,000 or so paid-up members of the Conservative Party.
After Mr Johnson and Mr Raab, the next most likely winners are Mr Gove, Mr Hunt and former Commons leader Andrea Leadsom, bookmakers say.
They are followed by International Development Secretary Rory Stewart, Defence Secretary Penny Mordaunt and Home Secretary Sajid Javid.
So far, only Mr Johnson, Mr Stewart and former pensions minister Esther McVey have declared their intention to stand.
"There's a lot of runners and riders in this particular race," Tony Travers, a politics professor at the London School of Economics university, told AFP.
Mr Johnson "would certainly be the party membership's choice but not necessarily members of parliament", he added.
AAP - SBS, AFP - SBS