Winegrowers in southern France, angry at the lack of government action to assist them in tough times, have claimed they were behind the blowing up of a signal box on France's TGV network.

The Winegrowers Action Committee claimed responsibility for the action which slowed traffic on the TGV near Narbonne and forced SNCF to deploy additional staff to keep installations secure.

SNCF said it would file a lawsuit against the protesters. The attack is a further escalation in the dispute between the farmers and the French government over the lack of state intervention to tackle the dual problems of over-production and competition in major markets from other countries. One grower was last week sentenced to six months in prison for an attack on government offices.