I keep looking at this chart and asking questions. If there was a deadly virus circulating at the START of last year, why no excess deaths BEFORE spring?
I've added general bed occupancy to show the NHS picture throughout the year.
I've got MANY more layers and questions to add

Same chart with Type 1 A&E (aka majors) added.

Same chart with adult critical care bed occupancy rates.

Just the deaths annotated with the first lockdown period

I've now created the excess deaths for 2020 for London using the ONS data

2020: https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/causesofdeath/datasets/deathregistrationsandoccurrencesbylocalauthorityandhealthboard
5yr Av: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/adhocs/12615deathregistrationsandfiveyearaverageweeklydeathsbylocalauthorityandplaceofoccurrenceenglandandwales2015to2019