Motorway petrol stations charge an extra 34p per litre as drivers embark on long car journeys

Motorway petrol stations are ripping off motorists by up to 34p per litre on fuel.

It can cost £18.70 more to fill up a family car on the motorway than at supermarket forecourts nearby.

The research, by the AA, exposes how fuel giants are hiking pump prices to cash in on rising traffic.

One example revealed a Shell garage on the M5 near Taunton, Somerset, selling unleaded at 133.9p a litre – compared with 99.7p at a Morrisons supermarket seven miles away.

The 34p a litre gap is one of the biggest price differences ever recorded by motoring groups. Although average petrol prices have gone up from 106.4p a month ago to 108p today, critics say the rise is not enough to justify the big increase in motorway prices when supermarkets sell fuel at around £1 a litre.

The increase is especially galling for motorists embarking on long car journeys for the first time after months of lockdown.Figures released yesterday show the UK got through 3.7billion fewer litres of petrol and diesel in March to May than in the same period last year, costing the Treasury £2.6billion in lost fuel duty as millions stayed at home.

The latest examples of fuel rip-offs come two years after former transport secretary Chris Grayling vowed to get tough on the issue, saying drivers were being ‘exploited’.

At the time, the Competition and Markets Authority urged the Department for Transport (DfT) to increase price transparency by displaying fuel price comparisons on the side of motorways.

But the idea was rejected by government experts and, despite promises of a phone app to help drivers trace prices, there has been no action since then. Motoring organisations are dismayed at the lack of progress and want Transport Secretary Grant Shapps to urgently address the issue.

The AA says current motoring petrol prices ‘are arguably at their most varied and ‘‘competitive’’ for years’. It identified three tiers of pricing, with the cheapest motorway petrol starting at 108.9p a litre, rising to 119.9p and then 133.9p.

Although many motorway services have kept their prices at the higher end, the AA points out that a minority have actually lowered prices to attract business post-lockdown.

However, drivers are unable to find out where those cheaper stations are because there is no official way of tracking prices. Surveys suggest one in five drivers put in just enough fuel ‘to get by’ on the motorway and wait for a cheaper alternative later, raising the risk they could run out of petrol – a scenario that would be particularly dangerous on smart motorways with no hard shoulder to pull into.

Motorway service stations insist they have to charge more due to the cost of building forecourts and running a 24/7 operation, but critics say the wide differences in prices are not fully explained to drivers.

Luke Bosdet, of the AA, said: ‘Two years ago, there seemed to be a real prospect of government creating competition, fair pricing and transparency for drivers. Today, as travellers leave the lockdown and go out on major routes again, there has still been no action.

‘The AA agreed with the Department for Transport that spending £50million on electronic fuel price signs along the strategic network was not money well spent.

‘Instead, officials started looking at a fuel-price app for mobile phones that would track prices along the motorways and allow drivers to trace the better deals.

‘So far, nothing. And drivers continue to face a pump price lottery if they decide to fill up on the motorway.’