Thanks Gaz. I've read the PHE report, but they don't publish the underlying data for some reason, so it's impossible to analyse.
It does seem to fly in the face of other data available. The total number of people in hospital with Covid-19 has continued to fall in all regions (including London), and although there were a couple of days in the past week where there were small rises in London, these were vastly outnumbered by the falls on the other days.
According to the Intensive Care National Audit and Research Centre, the number of people in ICU has fallen every day (with one minor blip) since 16th April. However, that data only runs until 22nd May and covers the whole of England, Wales and Northern Ireland, so it would be impossible to pick out a recent uptick in the London region alone.
I think we'll just have to wait until PHE publish next week's report to see if this was a blip or the beginning of a new trend. Bit frustrating though.