YouTube footage shows three young men posing high above the London skyline walking on the edge of the roof of a tall building under construction, and standing on top of what appears to be the mast of a hoist.
The building was not specified, other than that it is near Tower Bridge. The footage, filmed on 14th September 2016, shows it to be at fit-out stage.
Leader of the gang is a regular YouTube video blogger Louis Cole, aged 32, with friends Jacob and Harry, who appear much younger and are showing the way. It is apparent that they consider high-rise construction sites to be suitable playgrounds.
Clearly an industry response is required in the form of tighter security.