Schism that the Prime Minister said would never afflict his family

Ruthless dissection of the reported rift between David and Ed Miliband comes back to bite elder Johnson brother

‘In recent weeks I’ve been torn between family loyalty and the national interest – it’s an unresolvable tension & time for others to take on my roles’

Boris Johnson has always been adamant his family were too close to ever let politics get in the way. He had been scathing of David and Ed Miliband after the junior brother beat the senior in Labour’s 2010 leadership race.

Asked if he and his brothers were in any way similar to the Milibands, Mr Johnson, at the time London’s mayor, responded: “Absolutely not. We don’t do things that way, that’s a very Left-wing thing … only a socialist could do that to his brother, only a socialist could regard familial ties as being so trivial as to shaft his own brother.”

He didn’t stop there. “I mean, unbelievable. Only Lefties can think like that ... they see people as discrete agents devoid of ties to society or to each other – and that’s how Stalin could murder 20million people.”

Only he was wrong. Yesterday at just before 11am, Jo Johnson, 47, picked up his telephone in his office in the Department for Business, Energy and Industrial Strategy and rang his brother Boris, 55. None of the civil servants had noticed anything odd in his demeanour when he arrived at work shortly before 9am. “He was acting quite normally and giving people instructions,” said an insider. He even held a meeting first thing.

The call was matter-of-fact. “Jo made no ultimatums; he made no threats. He had already made his mind up and couldn’t be talked out of it,” said the source. Jo, the universities minister, told his brother he could no longer serve in his Government and he was also quitting as an MP. The message was clear: Jo could no longer even be part of Boris’s new-look Conservatives.

At 11.18am, shortly after the phone call, Jo went public, posting on Twitter: “It’s been an honour to represent Orpington for 9 years & 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 & time for others to take on my roles as MP & Minister. #overandout.”

Brexit has bitterly divided the Johnson family. Stanley Johnson, the patriarch of the family, journalist, author and unlikely reality television star, will be devastated. Yesterday, he was abroad and “thousands of miles away” but he now has the nightmare task of holding the previously always tight-knit family together.

“I am not talking about family matters. I am not talking about it, OK?” he said yesterday afternoon, sounding a little upset. “I am not talking about it. I am totally out of it. Everybody does what they have to do. I am an interested bystander.”

But the family is undeniably split. Jo

is married to Amelia Gentleman, an award-winning journalist with The Guardian, who embarrassed Theresa May’s government and forced the resignation of Amber Rudd as home secretary after exposing the Windrush scandal over the deportation of British residents back to the Caribbean.

Ms Gentleman has been highly critical of the treatment of European Union citizens applying for settled status in a post-brexit world.

Rachel Johnson, Boris’s sister, is also an ardent Remainer who stood for Change UK, the pro-remain party, in the European elections. Yesterday’s London Evening Standard claimed she had told the newspaper at an event earlier this week that the family’s arguments about Brexit were growing more fanatical by the day. She went on Twitter to deny it: “I’m afraid to say this is rubbish. I said last night at a charity do that the family avoids the topic of Brexit especially at meals as we don’t want to gang up on the PM!”

But Ivo Dawnay, her husband, was happy to weigh in. He congratulated Jo for quitting, even urging members of the Cabinet to follow suit: “Well done @Jojohnsonuk. Ahem, @Amberruddhr & @Matthancock, have you anything to say to the nation?” he posted on Twitter.

Staying out of the fray is Leo Johnson, the third youngest who avoided politics to become a Pricewaterhousecoopers partner and occasional BBC Radio 4 broadcaster. Sources suggest he, too, is a Remainer.

There is no doubt that yesterday’s resignation has caused a terrible rift in the family. Jo was only two and Boris just 10 when their mother Charlotte was admitted to the Maudsley Hospital in London for nine months after suffering a nervous breakdown.

Sonia Purnell, author of the biography Just Boris: A Tale of Blond Ambition, said: “They had to fend for themselves from a very early age and they were very close. So this resignation would not have been easy for Jo. The whole thing would have been very difficult. Jo used to look up to his big brother. There was real hero-worship.”

There are differences too, said Ms Purnell. “Jo is very serious; he is much more cerebral and also much quieter. He is also less charming than Boris and definitely not the showman.”

The family is famously competitive. When Jo obtained a first class degree from Oxford, Rachel telephoned Boris (who’d got a 2:1) reportedly to say: “Have you heard the bad news about Jo? He got a First.”

The prospect of a hard Brexit has clearly made life difficult. Journalists who watched Jo turn up for Boris’s Tory leadership launch thought he looked distinctly pale at the prospect of his brother’s rise to No10. One joked to him: “You look like you are on the way to the gallows.” Jo replied: “One does what one has to do.”

Last night, the Johnson family were coming to terms with a rift that the opposition was quick to seize upon.

“Boris Johnson poses such a threat that even his own brother doesn’t trust him,” remarked Angela Rayner MP, Labour’s shadow education secretary.

Others joked that Jo Johnson had become the first minister to quit to spend less time with his family.

Time will tell whether the rift will ever heal.