UK PM Boris Johnson in trouble as senior ministers Rishi Sunak, Sajid Javid put in papers

In a big blow to embattled British Prime Minister Johnson, two of his senior Cabinet colleagues, including Chancellor Rishi Sunak, resigned on Tuesday, as they expressed their loss of confidence in his leadership amidst a spate of scandals.

The 42-year-old British Indian minister posted his resignation letter on Twitter soon after another senior Cabinet colleague, UK Health Secretary Sajid Javid, resigned.

The ministerial exits will come as a big blow to Johnson's leadership and follow a day of high political drama since a former civil servant spoke out about Downing Street's handling of allegations against recently suspended MP Chris Pincher.

"The public rightly expect government to be conducted properly, competently and seriously," Sunak tweeted. "I recognise this may be last ministerial job, but I believe these standards are worth fighting for and that is why I am resigning," he said.

It came soon after Johnson said he "bitterly regrets" giving Pincher a government role as Deputy Chief Whip after being made aware of a misconduct complaint against him.

"In hindsight it was the wrong thing to do and I apologise to everyone who has been badly affected by it. I just want to make absolutely clear that there's no place in this government for anybody who is predatory or abuses their position of power," he said.

Sajid Javid, a British citizen of Pakistani origin, in his resignation letter said, "We [Conservative party] may not have always been popular, but we have been competent in acting in the national interest. Sadly, in the current circumstances, the public are concluding that we are now neither."

"The vote of confidence last month showed that a large number of our colleagues agree. I regret to say, however, that it is clear to me that this situation will not change under your leadership and you have therefore lost my confidence too," he tweeted.