The average price of diesel at the pumps has fallen below the average price of unleaded petrol for the first time in more than 14 years.

According to Experian Catalist, which monitors dealers’ prices across the UK on a daily basis, the average price of diesel on July 28 fell to 116.28ppl compared with the averaged unleaded price of 116.64ppl.

The falling diesel prices have been reflected by the supermarkets over the last fortnight with Morrisons, Sainsbury and Tesco each cutting their prices and Asda setting a national price ceiling of 112.7ppl for diesel, compared with 113.7ppl for unleaded petrol.

Fiona Cincotta, a senior market analyst at said: “The good news for the public is these cuts could deepen further in the coming weeks as the supermarkets are actually passing on savings that they have been making since May. One such figure being thrown around is that the supermarkets could still afford to cut a further 4ppl on top of the latest announcements.”

RAC fuel spokesman Simon Williams commented: “RAC Fuel Watch records show diesel was last cheaper than petrol on 17 July 2001 so it’s great news for the 10.7 million diesel car drivers. When this happened last diesel was cheaper than petrol for two and a half months, but with a new supply of diesel being produced from Saudi Arabia there is a real chance that we may see the diesel price staying below petrol for some considerable time.”