A Norwegian daredevil who skied down an escalator in London's Angel tube station with a camera strapped to his head has posted video of his stunt on the net.
The footage has sparked fury among London Underground bosses, who say other travellers could have been seriously hurt - or even killed.
With a length of 60m and a sharp climb of 27.4m, the escalator housed at Angel tube station is the longest in Europe.
The skier made the rattling descent in just ten seconds and hit the bottom with a sharp jolt. His friends were waiting below to keep the run out clear and make sure no-one was hurt.
The stunt appears on an extreme skiing DVD called Mind The Gap, created by freestyle skiiers based in Norway. A London Underground spokesman denounced the film as "dangerous and irresponsible".
He said: "It could have resulted in serious injury or death, not only to the individual concerned but also other passengers.
"London Underground will press for the police to take the strongest possible action against anyone attempting a similar act on the Tube network."
The legendary escalator at Angel appears on several other YouTube clips, which feature individuals attempting to climb the down escaltor in the "reverse escalator challenge".