There's even a map:
https://www.theguardian.com/cities/2017/jul/24/pseudo-public-space-explore-data-what-missing
@Oliver Schick started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
There's even a map:
https://www.theguardian.com/cities/2017/jul/24/pseudo-public-space-explore-data-what-missing