Motorway service stations have been accused of profiteering after a survey of prices at 21 sites by insurance company Admiral.

The most expensive basket, made up of typical purchases at services was found in the South West where the total cost came to £15.78, compared with the cheapest in the North West where the same items cost £12.58. However, all service stations were more expensive than a supermarket, where the same items cost £6.11.

One of the most expensive items in Admiral’s basket was a sausage roll, a pack of which cost £2.69 at four service stations: Durham on the A1, Bothwell on the M74, Magor on the M4 and Sedgemoor on the M5. This compared with 80p at the Heart of Scotland services on the M8.

Another item in the basket was a bottle of Coke, which cost £2.49 at Leigh Delamere on the M4, but £1.09 at the Heart of Scotland services on the M8.

Admiral also compared basket cost by region with a bag of wine gums costing £3.29 in the South East compared with £2.69 in Scotland. However, at the supermarket a bag cost £1.00.

When it came to fuel, there was 13% variation in petrol prices across different regions and 11% in diesel prices. The most expensive motorway service station for fuel was in the West Midlands with petrol costing 135ppl and diesel costing 136ppl.

However, motorists filling up in South Wales could pay 119ppl for petrol and 122ppl for diesel. This compared with UK-wide average costs of 115.9ppl for petrol and 116.80ppl for diesel.

Alistair Hargreaves, head of service at Admiral, said: “A stop-off on a long journey is often not factored into people’s budgets and this is where unexpected costs mount up. The simplest way to save pounds is by planning ahead. Those who do have to buy snacks or fuel at motorway service stations will find they’re held to ransom.

“Filling up the car at your best value local petrol station, and stocking up with journey essentials before you set off, will ensure your journey is smooth and you don’t get weighed down with the heavy cost of a motorway sausage roll.”