DRIVERS who park gasguzzling 4x4s overnight in Paris are receiving an unpleasant surprise in the morning: flat tyres. A gang of young activists are deflating the tyres of what they regard as anti-social urban tanks which clog the narrow streets of the Left Bank.

Claiming kinship with Greenpeace’s war on motorised “climate criminals” in Britain, the group has immobilised dozens of Range Rovers, Mercedes, Jeeps and other upmarket quatre-quatres in the well-heeled sixth and seventh arrondissements since July.

To the amazement of furious owners, the police say that it is not a crime because property is not damaged. “We have had complaints, but it is not clear that any offence is being committed,” said an officer at the sixth arrondissement.

Owners may bring a civil action against the activists, who call themselves les Dégonflés, the deflated ones, or in slang, the chickens or scaredycats. Thanks, in part, to their internet site (http://degonfle.blogg.org), which shows pictures of deflating raids, they say that they have spawned other groups in Lyon, Rouen, Geneva and even Australia.

Like the protesters in Britain, who harangue off-roading mothers on the school run, the campaigners seem driven as much by social and political animosity as concern over climate change. The leader of the group, who uses the name Sub-Warrant Officer Joker, told The Times yesterday: “We think that our action makes the owners look like wallies. We operate once a week and we try to deflate 30 per evening.”

They expel the air slowly without setting off the vehicles’ alarms, fixing open bicycle pump hoses to the tyre valves and returning later to collect their equipment. They leave a leaflet explaining their action.

“Perhaps it’s cowardly that we prefer to be anonymous, but we have received death threats,” Joker added. “That’s perfectly in keeping with the mentality of the 4x4 people who want to crush everything in their path.”

Christophe Delabre, president of the French 4x4 Federation, said: “This is an act of vandalism verging on terrorism, which could put lives in danger.” But he agreed that all sides should lobby the manufacturers over clean fuel.