Lots to say about this. No 10 implying Mr Cummings’ wife didn’t travel to Durham and DC did in period before he got symptoms. But even if he was asymptomatic, his wife wasn’t. Guidelines at the time said all members of her household should self isolate at home for 14 days. https://twitter.com/bethrigby/status/1264125635938660352

Number 10 are also saying that Durham Police is lying, which is a remarkable allegation to make.

The guidelines make clear that members of an infected household should not leave home. It would have been possible for members of an uninflected household (ie Mr Cummings’ sisters) to travel to London to help but not the other way around.

Also worth saying that the article written by Mrs Cummings seems very much at variance with this account, where she wrote of the couple’s joint experience of coronavirus.

At the time, Londoners were being urged not to travel to second homes or the rest of the country, given it was the epicentre of the UK outbreak at the time- indeed, we later learned that ministers even considered a London specific lockdown.