UK Prime Minister Theresa May announced on Friday her resignation, finally bowing to intense political pressure over the failure to deliver her signature policy - Britain's withdrawal from the European Union.

In a speech she held outside her residence at Downing Street 10, May said she would quit as leader of the Conservative Party on June 7, but would stay on as Prime Minister until a successor is chosen.

May was forced into making the announcement after losing the support of her Cabinet, many of whom were fed up with the ongoing turmoil over Brexit.

The last straw for Cabinet ministers appears to have been the latest version of May's Brexit plan, which she unveiled on Tuesday. In an attempt to win over opposition lawmakers, May offered the House of Commons the chance to vote on a second referendum – a concession that was bitterly opposed by some senior members of her government.

Her fate was sealed by the leadership of the 1922 Committee – which represents the interests of rank-and-file lawmakers in May's Conservative Party – who threatened to change party rules to allow a vote of no-confidence. May survived an earlier confidence vote in December last year, and under current rules was immune to challenge for another year.

May's announcement will set off a frantic race to succeed her. One leading candidate is Boris Johnson, the buffoonish but wily former Foreign Secretary who commands significant support among grassroots members of the party.

Johnson has bitterly opposed the withdrawal deal that May negotiated with the EU, and resigned from her Cabinet over it. But it's unclear whether her successor would have any luck reopening the deal, which Brussels has insisted is locked down. May's successor as prime minister will face the same deadlocked House of Commons, which has repeatedly rejected May's plan but failed to vote in favor of any kind of alternative.

That may raise the prospect of a new Conservative leader calling a general election in an attempt to break the impasse.

May's decision to step down is an inglorious end for a prime minister who was ushered into office on the back of the Brexit vote, promising to deliver on the results of the referendum.

But the deal that resulted from a tortuous set of negotiations with the EU was rejected three times by the House of Commons.

On Tuesday, in an attempt to repackage the plan, May rolled it up into a wider set of legislation dealing with Britain's departure. As well as the offer of a second referendum, it also contained pledges on workers’ rights, environmental provisions, as well as a temporary customs relationship with the European Union.

But her “new Brexit deal” was greeted with significant opposition from across the political spectrum. Hardline Conservatives who had supported May's last deal, Democratic Unionist Party (DUP) MPs who prop up May's minority government in Parliament and supporters of a second referendum alike all rejected it.