As is so often the case, the trickiest part came when he had to explain himself to his family.

''I got kind of a lukewarm response,'' said the masked Englishman who calls himself Angle-Grinder Man and who has been trawling London for four months dressed in a homemade superhero outfit, complete with gold lamé underpants and cape, removing the security boots from people's illegally parked cars.

''Any parent who gets a phone call from his son saying, 'Oh, you might see me in the newspaper; I'm a superhero wheel clamp vigilante' -- it might take them a little while to formulate their views,'' he said in an interview.

As a one-man vigilante force, Angle-Grinder Man, who takes his name from the boot-destroying circular saw he wields, has made only a modest impact: by his own estimates, he has freed about 20 cars so far (he does it only part time). But his campaign against the city's effort to immobilize cars for parking violations and other infractions has touched a nerve in a city of strict parking regulations, zealous traffic police officers, ubiquitous speed cameras and car owners increasingly aggrieved at what they believe is mean-spirited law enforcement.

Although he hardly melts into the background, particularly when he switches on his noisy machine, Angle-Grinder Man has so far managed to elude the authorities by a mixture of luck, cunning and quick work: once he gets going, he can liberate a car in less than a minute. He does not accept money and says his main motivation is ''anger at how politicians in this country treat people in general, but particularly in regard to motoring regulations.''