Boris Johnson has resigned as Foreign Secretary throwing the Prime Minister's latest Brexit proposals into turmoil.

His decision came hours after David Davis quit as Brexit Secretary, saying he would have been a "reluctant conscript" to Theresa May's vision for Britain's future outside the EU.

She had outlined her plans to the cabinet at her Chequers country retreat on Friday.

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The Prime Minister told Parliament this afternoon that the cabinet had agreed a "comprehensive and ambitious proposal" on how to take the Brexit negotiations further.

Mr Johnson appeared to have fallen in line with his colleagues behind the plans set out by the Prime Minister.

A Downing Street statement said: “This afternoon, the prime minister accepted the resignation of Boris Johnson as foreign secretary.

"His replacement will be announced shortly. The prime minister thanks Boris for his work.”

The decision has been met with surprise by some party members in the county, but not others.

Paul Cooper, vice chairman of the Faversham and Mid Kent Conservative Association, said the resignations of two senior ministers could mean a leadership challenge.

“I find it very hard to believe that Boris Johnson would want to just saunter off into the sunset and that this was not part of some pre-determined plot.

"So, I’d be surprised if there wasn’t a challenge to her leadership.”

Grass roots activists wanted stability in government, he added.

“Theresa May must consider whether she is the right person to deliver Brexit and if not, then she must consider her position.”

The danger was that the EU could seek concessions to the deal brokered by the PM and what was already a “soft” Brexit would become even softer.

Mike Whiting, chairman of Kent Area Conservatives, said: "Boris Johnson's resignation is a real surprise, particularly following the resignation of former Brexit Secretary David Davies.

"The Prime Minister will be speaking soon in Parliament and, like many other, I will be waiting to hear her response to these events."

Jeremy Hunt, the UK's longest-serving Health Secretary, has taken over from Mr Johnson as Foreign Secretary.

Dominic Raab was appointed the new Brexit Secretary this morning.

Kent Conservative MEP Richard Ashworth said the Prime Minister’s future need not be under threat.

“In fairness, she is doing her best to find a position around which the party can unite," he said.

"Yes, you can say well, two ministers have resigned but there are 20 who have not. But time is running out fast. The policy was work in progress and it was something I felt I could support.

“I think she has been doing a good job as Prime Minister but appreciate there are those that do not. Personally, I think the deal was the right way forward.”

Politics lecturer Professor Richard Whitman at the University of Kent said: “This demonstrates that even when the government has a Brexit strategy it is still divided within itself.

"This could be a turning point in Brexit possibilities because it is going to change the parliamentary arithmetic.

"This could make it more difficult for the government as Theresa May’s strategy has been not to commit on the fine detail of what she means by Brexit.”

Kent Labour MEP John Ashworth said: "I'm very pleased to see Boris Johnson out of the Government.

"If people in the UK could see just how his buffoonery has damaged the British interests abroad they would have been begging the Prime Minister to get rid of him long since.

"I hope his successor is a wiser, calmer figure.

"All this clearly leaves the Government in a position where they are still struggling to unite around anything and have failed to negotiate anything of substance.

"If Westminster can't agree then one way of other matters will have to return to the people."