A bout of in-fighting within Boris Johnson's team of close advisers has called into question the British government's focus on the dual urgent tasks of securing a post-Brexit deal with the EU and tackling the coronavirus pandemic.
The prime minister’s top adviser Dominic Cummings had planned to step down at the end of the year amid a power struggle at the heart of the British government.
The battle is fuelled by tensions over the UK's future in Europe as well as the health crisis and its economic fallout.
On Thursday night the controversial figure, whose combative style has sparked hostility among ruling Conservative MPs, told the BBC that he planned to be “largely redundant” by Christmas.
Speculation over Cummings' future had intensified since the resignation late on Wednesday of key ally Lee Cain, director of communications in the prime minister's Downing Street operation. This followed reports of bitter arguments among rival factions over a proposal to promote him to chief-of-staff amid a wider reorganisation.
Both Cain and Cummings worked together on the 2016 Brexit referendum campaign that was largely fronted by Johnson.
The upheaval in the upper echelons of the British government comes as post-Brexit talks with the EU go deep into stoppage time, with only days left to strike a deal on trade and the future relationship.
The UK left the EU last January but the transition period which keeps the UK in the bloc's economic structures expires on December 31. Time is running out to allow any agreement to be ratified and preparations made.
Despite progress in some areas, talks are still stuck on key issues including fishing rights and competition rules.
EU affairs blogger Jon Worth told Euronews that the chances of a no-deal stand at 50% at the moment - but "whatever happens, there's going to be disruption ahead" anyway.
If a no-deal happens, however, it could be "perhaps easier for Downing Street to communicate to the British population", he added, "because they can point the finger at Brussels saying 'Look, all of this crisis that we face...it is all the fault of Michel Barnier and the European Commission'."
"If Boris does do a deal, and then there is still chaos, it is actually harder for him to sell to the British public. So it's still on a knife-edge," Worth said.
Relations have been soured further by the government's Internal Market Bill currently going through parliament, which would override parts of the Brexit divorce deal on arrangements for Northern Ireland and breach international law.
Major changes are due from January when the UK leaves the EU's Single Market and Customs Union, and failure to strike a deal would aggravate disruption and costs.
The EU's chief Brexit negotiator Michel Barnier met again with the British side for talks, and tweeted to say that during a break walking in a London park he went looking for "level playing fields" among the football pitches -- a reference to one of the main sticking points relating to future competition.
Also on Thursday, the United Kingdom posted its biggest one-day jump in laboratory-confirmed coronavirus infections as the government reported 33,470 new cases. More than 50,000 people have died from COVID-19 in the country, which is Europe’s deadliest toll.
The government has imposed a one-month national lockdown on England that is scheduled to end on December 2. Temporary lockdowns end this week in Wales and Northern Ireland, while Scotland has a multi-tier system of local restrictions.
There are concerns that the economy will shrink again over the winter months amid the fresh curbs on everyday life across the UK, compounded by the uncertainty around whether a post-Brexit trade deal with the European Union will be reached.