I don't get it. If the new variant doubles very say or two how is the number from yesterday less today?
My hypothesis on what is happening that I think fits the data. Omicron is a huge percentage of everyone in a pub or restaurant on the weekend of the 10/11/12 got infected, this led to the peak on the 15th, doubling rate really relevant, we just know it's high enough to infect lots of people in the pub - everyone who hadn't had a booster in the previous few days or had delta, and still maybe 10-20% of both of those. That's how infectious it was.
Now the positive thing that being so infectious was, that now there are no big susceptible groups, so it doesn't matter that R0 is still really high, because there's now no places where you could meet that many - the people still going to the pub were the groups who made it through the first weekend unscathed - ie the genuinely likely won't catch it. Anyone who was unsure about going to the pub cancelled.
So now it's only small numbers of contacts, with the susceptible being even lower, Rt will have dropped to ~1 in the london area because there's not the large groups still available to infect.
The problem comes, is are the ones who still can be infected a much more vulnerable demographic and even if R is 1, will those catching it be 90,000 over 60's, when last week we had 90,000 20 year olds.
I also do wonder if the k-factor of omicron is even more extreme, and there are massive super spreaders taking out entire pubs, but lots of people don't produce at all - we certainly have anecdotes of omicron +ve people never managing to trigger an LFD, so that's still low viral load individuals? But no evidence at all of that yet.