[WATCH] Theresa May announces she will resign as Prime Minister on 7 June

Theresa May has said she will be resigning as Prime Minister and Conservative Party leader on 7 June.

Her announcement on Friday morning comes after three years in which she failed to deliver Brexit, and triggers the start of a contest to replace her as Britain's Prime Minister.

“I have done everything I can to convince MPs to back that deal... sadly I have not been able to do so,” May said in a statement at Downing Street.

She confirmed the process to select a new leader will begin in the following week, insisting it would continue to remain a source of great regret for her that she failed to deliver Brexit. 

Quoting British humanitarian Sir Nicholas Winton, she said “compromise is not a dirty word”.

May said she was sure the Conservative Party would serve people in the years ahead, and emphasised that the importance of the Office of Prime Minister was to fight “burning injustice”, the phrase she used at the beginning of her premiership.

“Our politics may be under strain but there is so much that is good about this country. So much to be proud of. So much to be optimistic about,” she said, adding that it was “the honour of [her] life” to be the “second female prime minister, but certainly not the last.”

Since January, Parliament has thrice rejected the withdrawal agreement May negotiated with the European Union. Recent attempts to find a formal compromise with Labour also failed.

May had planned a final bid to put the withdrawal deal Bill through Parliament on Friday, describing it as "one last chance" to deliver Brexit.

However, her proposals, which included a customs union arrangement and an offer to give MPs a vote on holding another referendum, angered many Tories.

Labour accused her of wanting to present a mere "rehash" of the original agreement, and declared they would not support her plans.

On Thursday, May met Home Secretary Sajid Javid and Foreign Secretary Jeremy Hunt at Downing Street, where they were understood to have expressed their concerns about the bill.

May's resignation comes after Andrea Leadsom stepped down as Leader of the House of Commons on Wednesday in protest at May's Brexit strategy.