The threat by textile workers in Givet, on the FrancoBelgian border, to blow up their chemical-packed factory may seem unbelievable but, in a sense, it is a natural progression from the official tolerance of political and social violence in France.

The threat by textile workers in Givet, on the FrancoBelgian border, to blow up their chemical-packed factory may seem unbelievable but, in a sense, it is a natural progression from the official tolerance of political and social violence in France.

It has become almost common for workers with a grievance to kidnap their managing director, block a motorway or destroy competing foreign produce. The reaction of the French authorities is always languid. Prosecutions rarely follow.

The official view is that politics and social unrest in France is traditionally played out in the street. It is better to let such protests work themselves out than to inflame them by opposing them.

In 1994, French fishermen burned the historic Breton parliament in Rennes. There were no convictions.

In 1998, cereal farmers invaded and smashed up the office of the Green environment minister, Dominique Voynet. They were defended by centre-right politicians. There has been talk of prosecutions but no action so far.

When the small farmers' leader José Bové was on trial recently for destroying a half-built McDonald's restaurant last year, he was lionised in the French press and even praised by the Prime Minister, Lionel Jospin.

What Mr Bové did was a mild act of terrorism. What the Givet workers are threatening to do - to blow up their factory unless they receive higher redundancy payments and job guarantees - is a full-blown act of terrorism. Whether they go ahead with their threat or not, they are using the fear of widespread destruction of property and pollution of the environment to enforce their demands.

This is terrorism, although the French government prefers to call it blackmail. Either way, on past evidence, Paris is likely to solve the problem by caving in.

In a way, the Givet workers are behaving rationally. As one woman sitting in at the factory said yesterday, violence always gets a reaction from the official classes in Paris and usually a positive one. Having seen other groups of workers use violence successfully in the past - farmers, lorry drivers - the desperate textile workers of Givet seized the only weapon they had: the explosives and chemicals stored in their factory.

There is an escalation going on here. Standard industrial violence - kidnapping senior executives or blocking roads - has now become so commonplace as to be relatively ineffective. The Cellatex workers in Givet have pushed the logic of industrial or social violence one stage further.

What next? Disgruntled Dassault workers buzzing the Prime Minister's office in Mirage jets?