Fuel prices have risen for the second month running, with petrol and diesel both increasing, new analysis from the RAC suggests.

Petrol went up by almost a penny a litre and diesel by almost 2p in July.

The average price of a litre of unleaded at the end of July was 135p – up 0.85p from 134.15p at the start of the month, while diesel rose by 1.64p from 141.21p to 142.85p. 

The increases follow respective rises of 2p and 3p in the previous month, which means the price of petrol has gone up almost 3p and diesel by 4.5p since June 1.

Consequently, the cost of filling a 55-litre family car now stands at £74.26 for unleaded and at £78.57 for diesel.

Petrol is also now at its most expensive point since mid-April, whereas diesel was last at its highest in the third week of March this year. 

RAC fuel spokesperson Simon Williams said: “While the average price of petrol for the year so far is just a couple of pence above the average for all of 2021, drivers are still meant to be benefiting from a 5p-a-litre fuel duty discount (52.95p as opposed to 57.95p) which has been in place since the start of the Ukraine War in early 2022.”

Filling up at a supermarket remains considerably cheaper with a litre of petrol averaging 131.5p and diesel 139p – both almost 4p less than the UK averages.

Northern Ireland remains the cheapest place to buy fuel in the UK, with a litre of unleaded averaging just 128p and diesel 134.5p.

This is just slightly more than the price at membership-only retailer Costco, which was charging an average of 125.6p for petrol and 133.2p for diesel at its 20 forecourts across Great Britain at the end of July.

In England, unleaded prices off the motorway range by 34p from 125.7p to 159.9p. In Scotland they go from 125.7p to 152.9p (27.2p) and in Wales from 127.7p to 142.9p (15.2p).

In Northern Ireland however, there is just 12p difference between the lowest and highest prices (124.9p and 136.9p).

Williams said: “Our analysis of the difference between wholesale and retail prices shows retailer margins remain high, particularly on petrol. This is emphasised by the fact the average price of unleaded in Northern Ireland is 7p cheaper than the average across the UK.

“Drivers may also see significant differences on forecourt totems from area to area which can be very frustrating. To buy the best value fuel it’s important to keep an eye out for the lowest prices around.”

Fleet News has teamed up with Allstar to bring you the UK fuel prices locator, enabling you to compare petrol and diesel prices and find the cheapest petrol or diesel in your area.