The prices of both unleaded petrol and diesel at UK forecourts are now falling more quickly than at any other point in 2024 so far, with both fuels now nearly 7p cheaper than a month ago, RAC Fuel Watch analysis shows.

As of Thursday (19 September), a litre of unleaded is being sold for 136.15p on average – down 5p since the start of September (141.26p) and almost 7p lower than a month ago (142.86p), saving nearly £4 for a complete fill-up. For diesel, the drop is similar with average prices down 5p since the start of the month (145.99p) to 140.87p, and nearly 7p lower than a month ago (147.74p). The recent sharp reductions mean that both petrol and diesel are now at their cheapest prices in almost three years.

The last time prices were dropping as quickly over the course of a month was between late November and the end of December 2023, when average prices at the pumps for both fuels reduced by more than 7p – but even then, prices on forecourts were considerably higher than they are today. The good news for drivers this month is that depending on where they shop, they can find prices well under the average, with supermarkets currently charging 133.23p for unleaded and 137.69p for diesel. In Northern Ireland, where the RAC considers pump prices to be at their fairest, a litre of petrol is just 131.5p and diesel 134.2p.

The RAC expects average pump prices to fall to a three-year low as soon as the end of September and, if prices continue to drop as the RAC hopes, the average cost of a litre of petrol could dip to as low as 132p and diesel to 138p within the next fortnight – which would be the lowest price drivers have paid for either fuel since July and September 2021 respectively.

The reason for tumbling pump prices is two-fold – a relatively low oil price of $73 brought about by lower global demand, combined with a relatively strong pound, with the latter being helped by a fall in the UK’s rate of inflation.* With fuel traded in US dollars, a stronger pound means UK fuel retailers get more ‘bang for their buck’ when buying in new stock on the wholesale market.

RAC fuel spokesperson Simon Williams said: “It’s really encouraging to see pump prices coming down so rapidly, which we know is as good for drivers’ wallets as it is for keeping the headline level of inflation in check.

“Of course, global oil prices and even the strength of the pound can fluctuate wildly and that’s something completely out of drivers’ control. But with the cost of filling up making up a sizeable chunk of many households’ overall monthly spending it makes sense to stretch every pound spent on fuel as far as possible. Driving efficiently – for instance, with a ‘light right foot’ and by changing up to as high a gear as possible – is the best way to do this, along with paying less to fill up in the first place.

“The message to drivers is simple – keep shopping around for fuel and use the available free tools out there, like the myRAC app, to always pay the lowest price wherever you can. We publish averages on our app and website to help drivers see the absolute maximum they should ever be paying, but there are some good deals out there if you know where to look.

“Based on wholesale pump prices, which is what retailers pay to buy the fuel in the first place, we know there’s scope for further price cuts so we very much hope that within the next few weeks we’ll see pump prices reach their lowest levels in three years. And, as our analysis clearly shows, it’s drivers in Northern Ireland who continue to get the best value with pump prices there between 5.5p and 6p cheaper per litre compared to the average across the whole of the UK.

“We continue to look forward to the new Government proceeding with its plans to introduce greater pump price transparency with the Pumpwatch scheme, along with an official monitoring function that can help ensure drivers are charged a fair price every time they fill up.”

Drivers looking to save money on their fill-ups should take advantage of the fuel finder feature in the free myRAC app. The app can be downloaded for free from the App Store or Google Play. Up to 10 searches a day can be made over a two, five or 10-mile radius, with each giving the five cheapest prices.

The RAC Fuel Watch web page 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 as well as a daily financial breakdown of the cost of a litre of petrol and diesel.