Signs to help drivers compare the cost of motorway fuel have been in the pipeline for two years. But ministers still can’t say when the scheme will be up and running.

Drivers continue to face sky-high motorway fuel prices because the government is dragging its heels on plans to increase competition between service stations.

Investigation carried out by Office of Fair Trading in 2013 found that fuel prices were typically 7.5p a litre more for petrol and 8.3p more for diesel on motorways.

The watchdog recommended that a network of signs which compared fuel prices at all the service stations should be placed on upcoming sections of motorway.This would enable drivers to use the best-value retailer, and the competition would help force prices down and make driving cheaper.

At present, service stations can get away with charging higher prices for fuel as well as for other amenities, because drivers are unable to shop around for cheaper deals.

The OFT’s suggestion was initially welcomed by ministers, with David Cameron announcing in May 2013 that he had ordered the Department for Transport (DfT) and the Highways Agency to begin work on developing a network of signs.But more than two years later, Britain still awaits its first motorway fuel price sign.

Meanwhile, Figures published by the AA at the end of July showed that while the average price for both petrol and diesel was 116.6p a litre, costs on the motorway were more than 10p a litre higher. Service-station diesel cost as much as 127.9p a litre while petrol cost 125.9p a litre at the time the research was carried out.

The government now appears to have changed its tune and is going back on what it clearly stated about a national roll-out in last year’s Autumn Statement and Motorists needing to buy fuel on the motorway continue to be forced to pay over the odds for no apparently good reasons, instead of seeing how these signs work in practice and whether drivers find them a benefit.