Earlier this year David Cameron famously declared that Brits don’t quit.

But on Monday after just two months on the backbenches the former Prime Minister announced that he had had enough.

In a move that shocked Westminster, Mr Cameron said he was standing down from frontline politics, just weeks after saying he intended to remain an MP.

The former Prime Minister said he did not want to be seen as a 'distraction', remarks widely seen as signalling his discontent with policies being pursued by his successor Theresa May.

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His announcement sparked a wave of condemnation from rival parties who accused him of breaking his contract with voters and leaving "the rest of us to pick up the pieces" of his failed bid to stay in the European Union.

Even self-proclaimed friends did not pull their punches on how he would be remembered.

The pro-European Tory MP Ken Clarke was blunt.

"His legacy will be he is the man who accidentally caused Britain to leave the EU,” he said.

Former First Minister Alex Salmond said that he thought Mr Cameron's resignation was "wrong".

He said he could understand a former Prime Minister worrying that everything he said would get "cast up against your successors".

"But I think it is wrong that he is standing down," he added.

"When you stand for election you make a contract with the voters. I think he should have served out his term and honoured his contract with his constituents."

He added: "I understand his frustration that he is no longer the main man, I understand that extremely well, but that is not good enough.

"You keep your mouth shut, you do your constituency buses, serve out your term."

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Mr Cameron denied he was standing down in protest at Mrs May's controversial new policy on grammar schools.

But one Labour MP said: “MPs who back their leader’s policies are not usually seen as 'distractions'.”

In a statement Mr Cameron said that he had considered his position over the summer.

He said that the “realities" of modern politics meant that it would be difficult for him to continue on the backbenches without “becoming a diversion”.

He paid tribute to the new Prime Minister and said that he had “every confidence” that Britain will thrive under her leadership.

But at just 49, he gave no hint of his plans for the future saying only that he wanted to continue with public service.

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Mr Cameron also said that he was sure he would be remembered for Europe, but perhaps not in the way many might imagine.

He predicted that he would be famous for “keeping that pledge to hold a referendum when many people thought that promise would never be kept”.

He added that he hoped that people would also look at his time in office as one in which the economy grew and included important social reforms.

Scottish Secretary David Mundell echoed those comments, saying that his "achievements in rescuing our economy and in social reform will stand the test of time".

But Lib Dem leader Tim Farron said that he had taken a “politically motivated and short-termist gamble with our country’s future, and lost to the huge detriment of future generations.

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He now leaves the rest of us to pick up the pieces.”

Mrs May said she thanked him for what he had done for the Conservatives and the country and wished him and his family “well for the future”.

A by-election will now be held in Witney in Oxfordshire, a safe Tory seat.