When living in London from 2009 to 2017, I started to collect information about severe cycling accidents in the British capital.
The number of cyclists killed in London per year varies massively. On average, from 1986 to 2010 , 17.2 cyclists died per year. If there is any trend, there seems to be a slight decline in the more recent years. The average from 1986 to 1999 was 18.3 while from 2000 to 2010 it was 15.9. However, the yearly variation is huge. For example, in 2004 only 8 cyclists died. One year later the number rose to 21. The worst year as 1989 with 33 fatalities. (Detailled statistics about long term trends are available here.)
Please read my comments regarding the interpretation of the data and be also aware that is is not complete, especially for early years.
I left London in late 2017 and am not putting too much focus on the data anymore, but other people for now keep updating it.
If you know about severe accidents which are missing or have additional information about a listed incident please drop me an email: firstname.lastname@example.org
This table is available on Google Docs.