BORIS Johnson is standing down as the Tory MP for Uxbridge and South Ruislip, triggering an immediate by-election.

This comes after the Privileges Committee found he misled Parliament over lockdown-breaking parties at Downing Street and recommended a suspension of more than 10 days.

Boris Johnson said he was quitting because he was “bewildered and appalled” at the Privileges Committee’s investigation into him.

Mhairi Black, the SNP's deputy Westminster leader, said Johnson "jumped before he was pushed", adding that "no one in Scotland will be sorry to see the back of him".

The former prime minister said he had received a letter from the committee, which is investigating whether he lied to MPs over partygate ,“making it clear, much to my amazement, that they are determined to use the proceedings against me to drive me out of Parliament”.

READ MORE: Boris Johnson's resignation honours list published

He said: “I have today written to my association in Uxbridge and South Ruislip to say that I am stepping down forthwith and triggering an immediate by-election,” he said.

“I am very sorry to leave my wonderful constituency. It has been a huge honour to serve them, both as mayor and MP.”

He added: “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, by a committee chaired and managed, by Harriet Harman, with such egregious bias.”

The announcement, coming only hours after his resignation honours list had been published, means the Conservatives are likely to face a tough battle to hold onto the London seat at a by-election.

It was the second by-election triggered on Friday following former culture secretary Nadine Dorries’ decision to quit the Commons immediately, rather than wait until the next election.

Following the news of Johnson's resignation, deputy Labour leader Angela Rayner said: “The British public are sick to the back teeth of this never ending Tory soap opera played out at their expense.

“After 13 years of Conservative chaos, enough is enough.

“It’s time to turn the page with a fresh start for Britain with a Labour Government focused on the people’s priorities of tackling the cost of living crisis and building a better future.”

Black added: “Boris Johnson has jumped before he was pushed, and no one in Scotland will be sorry to see the back of him but he has also underlined the weakness of Rishi Sunak, who has no authority over the bitterly divided Tory party.

“Sunak has been utterly humiliated. On the day he was forced to accept Johnson’s dodgy honours list to shore up his position, his predecessor has stuck two fingers up at him and reminded everyone that Sunak was unable to take action for fear of a leadership challenge.

“This sordid Tory scandal is yet another reminder of how broken and corrupt the Westminster system is – and why it is essential that Scotland becomes an independent country, so we can escape Westminster control and get rid of unelected Tory governments for good.”

Johnson also used his resignation statement to deliver a stinging attack on Rishi Sunak’s Government.

“When I left office last year the government was only a handful of points behind in the polls. That gap has now massively widened,” he said.

“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.

“We need to show how we are making the most of Brexit and we need in the next months to be setting out a pro-growth and pro-investment agenda. We need to cut business and personal taxes – and not just as pre-election gimmicks – rather than endlessly putting them up.  We must not be afraid to be a properly Conservative government.

“Why have we so passively abandoned the prospect of a Free Trade Deal with the US? Why have we junked measures to help people into housing or to scrap EU directives or to promote animal welfare?

“We need to deliver on the 2019 manifesto, which was endorsed by 14 million people. We should remember that more than 17 million voted for Brexit."