GPS is being blocked within 17.5nm of central London (notaminfo.com)

17.5 nautical miles, about 20 miles or 32km

This is obviously due to the coronation this weekend.

Found via (with map): https://chaos.social/@jonty/110304516796283385

seventeen nanometers doesn't sound like very far

[dead]

As mentioned in the comments: "...That covers all of canary wharf area. Lot of data centers use gps for clock sync..."