Motorists will no longer be hit with rip-off petrol prices at motorway service stations under a Government crackdown which could see electronic signs erected at the roadside. Filling up an average car can cost around £10 more at motorway service stations than at other pumps, data shows. The scheme is being introduced just weeks after the Transport Minister warned high prices at motorway service station pumps were “exploiting” motorists, encouraging them to drive with dangerously low tanks. The vast majority of motorway services are controlled by Moto, Welcome Break and Roadchef.–– ADVERTISEMENT ––It means drivers approaching services are likely to be told the cost of petrol in pounds and pence, with electronic road signs as well as digital warnings also being considered.In Italy, where signs on motorway stations informing motorists of prices have already been introduced, average mark-ups have fallen by 20 per cent, the Competition and Markets Authority said. “As we’ve seen abroad, giving drivers information on prices before they stop can force service stations to compete and bring down prices.””We now plan to work with the government to make sure drivers get to see the prices of fuel on their journey so they can choose early to avoid getting stung”. The scheme is a joint project between the CMA, the Department for Transport, and Highways England which maintains the UK’s motorways. A CMA spokesperson said: “The fastest route to deliver savings for drivers on Britain’s motorways is to make sure they know how much they’ll have to pay before they fill up so they can choose the cheapest option and send a clear signal to those charging high prices. Last month in a letter to the CMA, Transport Minister Chris Grayling, “I am concerned that which are higher than any other forecourts may exploit users in a situation where there is less choice and competition and discourage motorists from stopping and refueling, when, for safety reasons, they should.”He cited an RAC study which warned that one in five drivers drove with “just enough petrol to get by” on motorways because of the prohibitively high price. Last night motoring groups welcomed the CMA and the Government’s decision to intervene to better inform motorists about fuel prices. A spokesman at the AA, said: “Millions of UK motorists who have learnt to avoid extortionate motorway service area fuel prices like the plague, welcome today’s intervention on this long-running motoring headache.” Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.