July sees fuel prices climb for second month running

Petrol goes up a penny while diesel jumps by almost 2p

6 August 2025

Fuel prices rose for the second straight month, with petrol going up by nearly a penny a litre and diesel by almost 2p, new analysis of RAC Fuel Watch data reveals.*

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

What’s more, petrol is now at its most expensive point since mid-April whereas diesel was last at its highest in the third week of March this year.

Filling up at a supermarket is 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).

RAC fuel spokesperson Simon Williams said: “Unfortunately, drivers heading into the busy summer holiday season will be met with rising prices at the pumps, as the cost of fuel increased in July for the second month running.

“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.

“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. Alternatively, start using a free mobile app such as myRAC to find the cheapest fuel near you.”The online RAC Fuel Watch resource has more information about the average price of petrol and diesel at the big four supermarkets and at motorway services. It also features graphs showing average prices since 2000.