Dominic Cummings, Boris Johnson’s chief adviser and architect of Britain’s exit from the EU, left his desk in Downing Street for the last time on Friday carrying a cardboard box and a trove of potentially dangerous secrets.
The prime minister told Mr Cummings to leave Downing Street after a week of acrimony at the heart of government, marking the end of an era in which Vote Leave officials dominated Mr Johnson’s operation.
Mr Cummings’ decision to walk out of the front door of Number 10 after what one official called “a day of tantrums” raised concerns that the adviser might turn against Mr Johnson and lift the lid on a chaotic administration.
One government insider said: “I won’t be surprised if there’s an explosive stunt between now and Christmas.” A colleague of Mr Cummings said: “It’s not Dom’s style just to quietly drift away.”
Mr Cummings declined to comment but he has never shied away from using his private blog to seek revenge on those who have crossed him. Lee Cain, Mr Johnson’s communications director, also quit his job on Friday.
Mr Cummings resigned after Mr Johnson indicated that he was going to cut loose the Brexit campaigners who had sustained his rise to power and helped him win an 80-seat Commons majority in December last year.
Mr Johnson held a 45-minute meeting with Mr Cummings and Mr Cain on Friday to discuss their “general behaviour” this week, according to individuals with knowledge of the conversation.
In tense exchanges, Mr Johnson accused his aides of briefing against him and his partner Carrie Symonds and criticised them for destabilising the government in the midst of tense Brexit negotiations.
Mr Johnson showed the aides text messages that had been forwarded to Ms Symonds, who opposed Mr Cain’s appointment as chief of staff, to show they had briefed against her. He told them to get out and never return.
Tory officials said Mr Cummings and Mr Cain would continue to do some work for Number 10 until mid-December but were expected to operate from home.
Mr Johnson, who refused to make Mr Cain his chief of staff, is looking to usher in a more consensual style of politics in 2021, more in tune with the conventional politics returning to the US under president-elect Joe Biden.
Mr Johnson’s remaining team inside Number 10 is braced for Mr Cummings’ revenge. Vote Leave advisers have complained privately about the prime minister’s inability to make big decisions and his lack of grip on detail.
“I’m told there is a blog coming. Spads [special advisers] are preparing about how to respond,” said one official. “It’s really the last days of Rome in here.”
Some say that Mr Cummings — who became frustrated at the slow progress in implementing his own agenda of civil service reform, defence reforms and science projects — will seek to blame Mr Johnson.
“Dom is going to have to face up to the fact that after spending years writing millions of words in his blogs, he has achieved nothing in government,” said one ministerial adviser.
Meanwhile, Downing Street has insisted that Mr Johnson is not going to back down in trade negotiations with the EU, in spite of the acrimonious departure of Mr Cummings and other Brexit hardliners.
Mr Cummings’ resignation comes ahead of a crucial phase in Brexit talks in Brussels next week, prompting speculation that the prime minister might have more political space to make the concessions needed to close a deal.
But Mr Johnson’s allies rejected any suggestion that he would soften his stance, saying that while the prime minister wanted a deal, it would only be concluded if the EU fully respected British sovereignty. “Policy will not change on this,” Downing Street said.
The prime minister fears that Brussels might misread the bitter power struggle in Downing Street as a sign of a weakening resolve in the trade talks. “The PM is always the toughest voice in the room on Brexit,” one official said.
Philippe Lamberts, a member of the European Parliament’s Brexit co-ordination group, said the ructions in Downing Street were a positive sign that Mr Johnson wanted a deal with the EU. The post-Brexit transition period ends on January 1.
“I do believe indeed that he’s making the choice of a deal,” Mr Lamberts told the Financial Times. “This puts him on a collision course with hard Brexiters such as Dominic Cummings.”
Kim Darroch, Britain’s former ambassador to Washington and Brussels, said any “weakening of the hold on policy” by Mr Cummings and his Vote Leave cadre of advisers would be a good thing.
Lord Darroch said that, if there were no trade deal, Britain could enter 2021 at odds with the US, the EU and China. US president-elect Joe Biden thinks Brexit is a bad idea and could harm the Northern Ireland peace process.
Speaking at the FT Global Boardroom event, the former envoy said: “Where exactly are our friends in this brave new world? That ought to worry us.”
Many Conservative MPs celebrated the departure of Mr Cummings, who has publicly spoken of his contempt for many Eurosceptic Tory MPs. “Rejoice,” said one MP, while another added: “Good riddance.”
Edward Lister, Mr Johnson’s longstanding ally from his days as London mayor, will be the new chief of staff in Downing Street for an interim period, pending a permanent appointment.
Get alerts on UK politics & policy when a new story is published