Theresa May has confirmed her resignation for June 7 after a tumultuous three years as the nation's leader.

In an emotional speech outside 10 Downing Street, Mrs May she said she had "done my best" to lead Britain out of the European Union as voted for in the 2016 referendum, but that it was "in the best interests of the country" that a new Prime Minister complete the process. 

She was tearful as she said she was leaving office "with no ill will, but with enormous and enduring gratitude to have had the opportunity to serve the country I love".

She admitted, however, that her failure on Brexit would be a source of regret. 

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

Her departure will trigger a Tory leadership contest, with former Foreign Secretary Boris Johnson the favourite to replace her.

The Bishop of London, the Rt Rev Sarah Mullally said she was praying for the country. 

"Praying for the Nation and the Prime Minister at this time. She has served with dignity in the hardest of political circumstances," she tweeted.  

Andy Flannagan, executive director of Christians in Politics, said: "I hope that the glimpse of raw emotion in Theresa May's speech reminds us that those who offer to serve as politicians are human beings just like us, fallen and at times frail, and that they need our prayers whether or not we agree with their decisions.

"And I hope that that realisation allows many more Christians to believe that they could be stepping forward into roles of service in public life. These jobs are not just for the 'special people'. They don't exist."

Faith Minister Lord Nick Bourne echoed the sentiments, saying that Mrs May's resignation speech was "so very dignified and heart rending".

"A clear message for the future leader - compromise is not a dirty word. The Prime Minister deserves enormous credit for the public service she has given to our country. Thank you Theresa May," he said on Twitter.

The Prime Minister's Special Envoy for Freedom of Religion and Belief, Lord Ahmad of Wimbledon, called Theresa May a "lady of principle, showing great devotion to her role with an unstinting and incredible sense of public duty - from justice for the families of Hillsborough to the security of our nation and equality for all-she served with great dignity".