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"A very sad but inevitable consequence of all that has happened," says Conservative MP Gareth Johnson.

"Now the Conservative Party has to take time to reflect on that statement and obviously go on to elect a new leader.

"There is plenty of new talent out there but the person to unite the party is Dominic Raab."

The PM was moved to tears when she ended her statement.

"Our politics may be under strain but there is so much that is good about this country, so much to be proud of," she said.

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

She begins to cry as she says she is grateful to "serve the country I love".

And with that she heads back into Number 10.

"I know that the Conservative Party can renew itself in the years ahead," she says.

"I know that we can deliver Brexit."

"I am proud of the progress we have made over the last few years," Mrs May says.

"We have helped more people than ever secure a job."

"It is a matter of deep regret that I have not been able to deliver Brexit.

"My successor will have to find a consensus.

"Consensus will only be possible if those on both sides of the debate 'compromise'."

"It is now clear to me that it is in the best interest of the UK for a new PM to lead that effort," she says.

"I am today announcing that I will resign as Conservative leader on Friday 7 June.

"I have agreed with the party chairman that the process for electing a new leader will begin in the following week."

She continues: "I negotiated the terms of our exit."

"I have done everything I can to convince MPs to back that deal.

"Sadly I have not been able to do so."

Theresa May says: "Ever since I first stepped through the door behind me as PM I have striven to make the UK work not just for a privileged few but for everyone and to honour the result of the referendum."

Theresa May begins her statement.

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Conservative Brexiter Steve Baker denies that his wing of the party has been campaigning to topple Mrs May, rather for a Brexit that "meets people's expectations".

He adds that would "give her credit for a great many things", adding that she has "behaved honourably" during negotiations with the EU.

He says he needs to "reach a decision myself" as to whether he runs to be the next leader, describing it as "conceivable".

He says a number of people have asked him to stand.

Tory MP Helen Grant, who resigned from her Conservative Party role this morning, said she will be backing Dominic Raab as Mrs May's successor.

She earlier resigned the role because she wants to "actively and openly support one of the new leadership candidates".

Conservative MP Damian Green - Mrs May's former deputy - spoke about what Mrs May's legacy might be on BBC Radio 4's Today programme earlier.

He said: "Prime ministers come in all forms of personality. Perhaps inevitably, people at the moment are concentrating on the downside, but we have to remember the extraordinary sense of public service.

"And actually, in an era when political discourse has become so poisonous and vicious, she was always courteous, always polite.

"I think, the thing that I regard as the biggest tragedy, if you like, politically, is that she could never have the time and space to implement her domestic agenda - the attack on the burning injustices that she saw."

Theresa May is expected to make a statement in Downing Street within minutes - at around 10:00 BST - Downing Street has confirmed.

A few moments ago, a member of the Downing Street staff came outside to take in Larry the Cat, No 10's "chief mouser".

The nine-year-old tabby cat has lived at 10 Downing Street since 2011.

Norman Smith
Assistant political editor

Theresa May has never had a solid base among Conservative MPs.

The cabinet could never be her base because she had to balance it between Leavers and Remainers.

The party membership are her people - that is where she has drawn her support from.

Therefore when the party membership called a vote of no-confidence in her leadership that would have been like her own pulling her down.

I think personally she would have found that very, very difficult.

Pressure on Theresa May intensified after she announced her latest Brexit proposals.

The key points of the revised plan are:

• A guarantee of a Commons vote on whether to hold another referendum on the government's Brexit deal, with a promise to honour the outcome
• A vote on different customs options, including a government proposal for a temporary customs union for goods - what Mrs May called a "customs compromise"
• A legal obligation for the UK to "seek to conclude alternative arrangements" to replace the Northern Ireland backstop by the end of 2020
• If the backstop does come into force, the bill would guarantee Northern Ireland remains aligned with the rest of the UK and remains in same customs territory
• Legislation to ensure workers rights are "every bit as good if not better" after Brexit and guarantees of no dilution in environmental standards
• A legal duty to seek changes to the political declaration on future relations with the EU