Last week, public health officials said they would need to see at least 250 hospital admissions with Omicron before being able to come to any early judgement about how severe this new variant is in people who catch it.
We are probably getting close to that point now. The latest statistics show there were 129 confirmed Omicron cases in English hospitals on Saturday and numbers are likely to have risen since then.
The BBC understands that a team at Imperial College are working on this kind of severity analysis at the moment - it is likely to form a key part of ministers’ decision making over the next few days.
The number needing hospital treatment in London, seen as the epicentre of England's outbreak, has been going up recently - 210 people were admitted with Covid last Saturday compared with 166 the previous week.
But as Prof Sir David Spiegelhalter pointed out on Channel 4 News last night, a significant proportion of those will have gone to A&E for a non-Covid reason and tested positive on arrival. The sheer size of the outbreak in London makes that more likely.
There are also some very early, tentative signs that the numbers needing Covid hospital care in the capital might be below the levels expected given the number of infections in the city."