Britain's former prime minister Boris Johnson angrily quit as a member of parliament on Friday, claiming he had been forced out in a stitch-up by his political opponents.

The 58-year-old populist politician has been under investigation by a cross-party committee about whether he repeatedly lied to parliament over Covid lockdown-breaking parties when he was in office.

In evidence earlier this year, he angrily insisted he had not.

But as the committee prepares to make public its findings, he said they had contacted him "making it clear... they are determined to use the proceedings against me to drive me out of parliament".

The Privileges Committee, which has a majority of MPs from his own Conservative party, has powers to impose sanctions for misleading parliament, including suspension.

Ordinarily, suspension of more than 10 working days leads to a by-election in the MP's constituency.

Johnson, though, pre-empted any finding -- or the consequences of a humiliating fight to remain an MP in his Uxbridge and South Ruislip constituency in northwest London where he holds a slim majority of just over 7,000 -- by quitting.

He denounced the committee, chaired by veteran opposition Labour MP Harriet Harman, as a "kangaroo court".

"It is very sad to be leaving Parliament -- at least for now -- but above all I am bewildered and appalled that I can be forced out, anti-democratically... with such egregious bias," he said.

The committee's report, which has not been published, was "riddled with inaccuracies and reeks of prejudice", he said, complaining he had "no formal ability to challenge anything they say".

Their "purpose from the beginning has been to find me guilty, regardless of the facts", he added.

Responding to the resignation, the Privileges Committee said Johnson "impugned the integrity of the House by his statement".

The committee said it would meet on Monday to conclude its inquiry and would publish its report "promptly". 

- Sunak attack -

The announcement came just hours after Johnson controversially rewarded his closest Brexit allies -- and officials implicated in the "Partygate" saga -- in his prime ministerial resignation honours list.

At the same time, his former culture secretary Nadine Dorries announced that she was quitting as an MP with immediate effect.

Johnson led the Tories to a thumping 80-seat majority in the December 2019 general election on a promise to "get Brexit done".

That allowed him to railroad through parliament his divorce deal with the European Union, unblocking years of political paralysis.

But he was undone by his handling of the Covid pandemic, "Partygate" and a succession of other scandals that led to a ministerial rebellion in July last year.

He quit as prime minister and left office in September last year, although rumours persisted that he wanted another shot at the top job.

Rishi Sunak, who was one of Johnson's top team who quit, has been trying to steady the ship since becoming prime minister in October last year, after the turbulent tenure of his former boss and the short-lived premier Liz Truss.

Johnson's resignation will likely be seen as his revenge on Sunak, whose Tories are well down in the polls to the main opposition Labour party after 13 years in power and with a general election looming next year. 

"When I left office last year the government was only a handful of points behind in the polls. That gap has now massively widened," said Johnson in his letter lashing out at Sunak.

"Just a few years after winning the biggest majority in almost half a century, that majority is now clearly at risk.

"Our party needs urgently to recapture its sense of momentum and its belief in what this country can do."

- 'Good riddance' -

Johnson's supporters rallied behind him, lauding his achievements on Brexit, and galvanising support for Ukraine.

But Labour's deputy leader Angela Rayner said the public -- battling a cost-of-living crisis -- have had enough of the "never-ending Tory soap opera".

Her opposite number with the smaller Liberal Democrats, Daisy Cooper, said it was "good riddance" while the Scottish National Party's deputy UK parliament leader Mhairi Black, said Johnson "jumped before he was pushed".

Johnson, who was sacked from his first job at The Times newspaper for making up a quote, made his name as Brussels correspondent of the Daily Telegraph peddling euromyths.

He first became an MP in 2001 until 2008, then quit to serve two four-year terms as London's mayor. He became an MP again in 2015, going on to be foreign secretary under Theresa May.

acl-phz/fb