The British prime minister's chief adviser Dominic Cummings has reportedly left Downing Street for good.
It was earlier reported he was quitting his role by the end of the year, but he now appears to have brought forward his departure with immediate effect.
Mr Cummings was well-known for playing a key role in the Brexit referendum before taking up his role in Downing Street.
Earlier this year, he was at the centre of a major controversy after it emerged he had travelled hundreds of miles during the coronavirus lockdown.
Despite calls for the adviser to resign over the controversy, he remained in his job after receiving the support of Mr Johnson.
John Rentoul, chief political commentator with The Independent, spoke to The Hard Shoulder to outline the background to today's dramatic departure.
He said: "Dominic Cummings made sure he walked out of the front door of No 10 carrying a cardboard box, with the lights on behind him... so it looks like a very dramatic shot.
"He could have gone out the back door and into an unmarked car and just slipped away... but he wanted the world to know he was going."
Mr Rentoul says it appears the exit appears to have been triggered by the potential promotion and then sudden departure of Mr Cummings' ally Lee Cain - something which led to a 'meltdown' within No 10 Downing Street.
He said: "Since the business about [Dominic Cummings'] driving all the way to Durham during lockdown... everybody in the country knows about that.
"He has been something of a drag on the ticket, as far as Boris Johnson was concerned. I think he should have gotten rid of him then.
"I think it strengthens the prime minister to get rid of him now. The way it's been done, obviously, hasn't been entirely smooth - so there is a danger to Boris Johnson that Dominic Cummings may want to hit back.
"But generally their departure should strengthen the prime minister, as it means he can revamp his appeal."
He added that Mr Cummings was "fantastically unpopular" among Conservative MPs.