BBC: Boris Johnson has until 22:00 GMT on Friday to answer the Metropolitan Police’s questionnaire about whether he broke lockdown rules at Downing Street parties.
The prime minister has been consulting lawyers about his response.
It is these private lawyers who are overseeing communications with the Met Police.
Sources close to Mr Johnson say he is funding that himself. The No 10 machine is being kept in the dark to avoid what one insider called a conflict of interest.
The prime minister has made it clear what his defence will be: that he both lived and worked in Downing Street, so had a reasonable excuse to be in the building and around the garden when controversial drinks gatherings took place.
Mr Johnson hopes that will be enough to get him off the hook – if it doesn’t, there could be a new wave of political crisis for the prime minister and more Conservative MPs could try and force him out.
Among Mr Johnson’s allies, there is a frank admission that they just don’t know for sure whether his explanation will work. But here’s how they think it might.
Firstly, there have not been many retrospective prosecutions for breaking lockdown laws.
Secondly, the prime minister has argued both publicly and privately that the events he was at can be reasonably seen as work. If he makes that case, will the Met have enough evidence to conclude he is wrong? The bar, some believe, is likely to be high.
Some of the argument delves a bit deeper.
Glasses of wine
It starts with the fact that the prime minister and some staff were required to be in the office to oversee the Covid response.
If they had a glass of wine at the end of the day – in an office they had a good reason to be in – was that really an illegal gathering?
Part of the answer to that, some think, might rest on just how many glasses of wine a certain person had.
The argument goes: if someone can prove they were at a gathering for a short period of time, then went to a meeting or to do something else for their job, this would still be classed as being at work.
That might be judged differently if they went on to get drunk late into the night – or, for example, if they broke the prime minister’s son’s swing, as has been alleged happened at one event in the Downing Street garden.
