The UK Prime Minister's brother Jo Johnson announced his resignation as a member of Parliament and Minister on Thursday, saying he was "torn between loyalty to his family and the national interest".
His shock resignation comes as his brother Boris Johnson, who at 55 is eight years his senior, struggled to command the House of Commons -- the UK's lower parliamentary chamber -- where the government was coming up against staunch opposition to its Brexit plan.
The Business Minister and Tory MP for Orpington, southeast London, cited an "unresolvable tension" in his role, the BBC reported.
"It's been an honour to represent Orpington for 9 years and to serve as a Minister under three PMs. In recent weeks I've been torn between family loyalty and the national interest - it's an unresolvable tension and time for others to take on my roles as MP and Minister," Jo tweeted.
He previously quit as a Minister over Brexit in 2018 under the leadership of Theresa May.
A Downing Street spokesman said: "The Prime Minister would like to thank Jo Johnson for his service. He has been a brilliant, talented Minister and a fantastic MP.
"The PM, as both a politician and brother, understands this will not have been an easy matter for Jo. The constituents of Orpington could not have asked for a better representative."
The news broke at a time when Johnson was grappling with Parliament over the UK's plan to leave the EU on October 31.
The UK's opposition parties, led by Jeremy Corbyn's Labour Party, have wrested the parliamentary agenda from Boris Johnson's government and have passed a bill designed to prevent the Prime Minister from pursuing a no-deal Brexit if he fails to land an agreement with the EU.
They also shot down Boris Johnson's proposal to slate snap elections on October 15, when Parliament is set to reconvene after the five-week prorogation controversially requested by the Tory leader.
Boris Johnson has already lost his working majority in the Commons, having removed the whip from 21 rebel Tories who voted against the government.
Former Cabinet Minister David Gauke, one of the MPs who lost the Conservative whip, tweeted: "Lots of MPs have had to wrestle with conflicting loyalties in recent weeks. None more so than Jo. This is a big loss to Parliament, the government and the Conservative Party."
Opposition figures were quick to jump on the latest departure from the government benches.
"Boris Johnson is such a threat that even his own brother doesn't trust him," said Labour's shadow education secretary Angela Rayner.
