UK Prime Minister Theresa May announced that she will step down as leader of the Conservative Party on June 7. The successor was expected to be in place by parliament's summer recess set for July 20, said the Conservatives.

"It is now clear to me that it is in the best interests of the country for a new prime minister to lead that effort. So I am today announcing that I will resign as leader of the Conservative and Unionist Party on Friday the 7th of June," May said in a statement outside her Downing Street residence, with her voice breaking with emotion.

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"It is and will always remain a matter of deep regret to me that I have not been able to deliver Brexit," she added.

The resignation will signal the formal start of a leadership contest. She would remain as prime minister in a caretaker role until a replacement is elected by the party. The leader of the party automatically becomes prime minister.

The leadership race is expected to take several weeks. Nominations among MPs would close in the week beginning June 10, before party members choose between the top two candidates "in time for the result to be announced before parliament rises for the summer," said the party's chairman Brandon Lewis.

He said that after nominations close, successive rounds of voting among MPs will whittle the contenders down to a final two. "We expect that process to be concluded by the end of June," said Lewis. 

"I feel as certain today as I did three years ago that in a democracy, if you give people a choice you have a duty to implement what they decide. I have done my best to do that," said May.

"I negotiated the terms of our exit and a new relationship with our closest neighbors that protect jobs, our security and our Union. I have done everything I can to convince MPs to back that deal. Sadly, I have not been able to do so. I tried three times. I believe it was right to persevere, even when the odds against success seemed high."

"I will shortly leave the job that it has been the honor of my life to hold – 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."

May, who took charge in the aftermath of the 2016 EU referendum, was forced to make way following a mutiny in her cabinet and Conservative Party over her ill-fated strategy to take Britain out of the European Union.

She will become one of Britain's shortest-serving post-WWII prime ministers, remembered for presiding over one of the most chaotic periods in the country's modern political history.

MPs have overwhelmingly rejected the withdrawal agreement she struck with European Union leaders last year three times, brutally weakening May on each occasion.

The Conservatives are expected to fare similarly badly in this week's European Parliament elections when the results are announced late Sunday.

Britain's Foreign Secretary Jeremy Hunt will stand for the leadership of the Conservative Party following the resignation of May, his local paper said on Friday.

Hunt said it was “only right that my party constituency should be the first to know,” the Farnham Herald reported Hunt as saying at the Haslemere Festival in southern England.

(Top image: British Prime Minister Theresa May delivers a statement in London, Britain, May 24, 2019. /VCG photo)

(With input from AFP, Reuters)