David Cameron is to stand down as MP with immediate effect, he has announced.
Mr Cameron, who has represented Witney in Oxfordshire since 2001, will trigger a by-election to find a successor for the area in Parliament.
He had stepped down as Prime Minister the morning of the 24 June European Union referendum result after it became clear he had accidentally taken Britain out of the bloc.
Mr Cameron told broadcasters he would not be able to properly represent his area given the circumstances of his departure as Prime Minister.
Backing Theresa May's premiership, he said also said he did not want to be a “distraction” for the Government.
“With modern politics, with the circumstances of my resignation, it isn’t really possible to be a proper backbench MP as a former prime minister,” he said.
“I think everything you do would become a big distraction and a big diversion for what the Government needs to do for our country. I support Theresa May, I think she’s got off to a great start, I think she can be a strong Prime Minister for our country.
“I don’t want to be that distraction. I want Witney to have a new MP who can play a full part in parliamentary and political life without being a distraction."
However, when quizzed about his support for grammar schools, Mr Cameron was less than effusive for his successor’s agenda of sweeping reform – though he denied they were related to his decision to stand down.
“There are very many good things in the policy. But frankly I don’t want to get into the whys and wherefores of this individual policy.
“My announcement today is not about grammar schools. There’s no connection with grammar schools, it’s purely one of timing.
“My view is, as I’ve said, I don’t want to be the distraction and diversion that the former prime minister inevitably is on the backbenches."
Mr Cameron added that he would continue to live locally and support local causes and charities – but that he would “obviously” have to “build a life outside of Westminster”.
“I want to thank everybody here in West Oxfordshire who have been so supportive,” he added.
The former PM said he had met with his consituency party chairman earlier this morning, as well as his staff in Witney and London, before making his public resignation statement.
Prime Minister Theresa May said: “I was proud to serve in David Cameron’s government – and under his leadership we achieved great things. Not just stabilising the economy, but also making great strides in delivering serious social reform.
“His commitment to lead a One Nation government is one that I will continue. I thank him for everything he has done for the Conservative Party and the country and I wish him and his family well for the future.”
The announcement, made in an interview, is a reversal of previous statements by the former prime minister, who had said he wanted to stay on.
In May this year he told BBC Radio Oxford that he was "very keen to continue" as an MP after the scheduled 2020 general election.
Asked whether he would stand at the time he replied: “That is very much my intention.”
Mr Cameron’s retreat from elected office comes after controversy over his resignation honours list. He was accused of awarding his “cronies” with honours: a Whitehall investigation has been launched.
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies