Tanker drivers contracted to Shell are set to follow up the strike that started this morning with another four day action next week if employers do meet their pay demands. More action is scheduled for next Friday (June 20), with another strike starting at 6am and running until Monday. Around 500 drivers working for transport company contracted to Shell are striking over proposed pay increases. They had rejected an offer of up to £41,500, up from £32,000. Despite the strike, which will afflict supplies to one in ten UK filling stations, the Petrol Retailers Association (PRA) said that the country was not in the grip of a full scale crisis after reports that other fuel companies were being affected. A spokesman for PRA said: "Other companies are not currently involved it is still entirely a Shell matter." Reports have said BP drivers were not crossing picket lines at fuel depots. He added: "Fuel traffic has been up around 25% but only at petrol stations situated on busier roads. It is looking a little bit busier than a normal Friday, but if people only buy what they need we won't have a problem".Reports of Shell petrol stations already running dry in the south of England won't help matters, as the government asks the public to stay calm and avoid panic-buying of petrol and diesel. Prime Minister Gordon Brown has said the Army are a possible back up to get fuel to where it's needed, but that government response will be proportional to the level of disruption. In the meantime, the AA has warned the UK's motorists not to waste a single drop of fuel, by cutting out short journeys, sticking to speed limits, and critically avoiding queuing up at petrol stations.