Pump prices are continuing to rise, with new data from RAC Fuel Watch suggesting diesel is now almost 20p dearer than at the end of May 2020.

Diesel has suffered a 14.4p hike in the last six months alone.

Petrol has also risen sharply and is now more than 22p a litre more expensive than a year ago – the biggest 12-month increase seen for 11 years, says the RAC.

At 129.27 pence per litre (ppl), unleaded is now more expensive than it was at the start of 2020 prior to coronavirus pandemic – a price last seen in mid-August 2019.

Diesel, however, at 131.59ppl has not surpassed the 132p a litre it reached at the end of January 2020.

This means a full tank for a 55-litre family car will set drivers of petrol cars back £71.10 and diesel cars £72.37 – around £8 more than before the non-stop rises began in November, says the RAC.

The newly published data shows that unleaded went up by more than 2p a litre (2.24p) in May to 129.27ppl, while diesel also increased by a similar amount (1.95p) to 131.59ppl.

In the seven months since the country last saw the average price of petrol fall (November 2020) petrol has increased by 15.5p.

The 22p surge in the price of petrol followed a litre dropping to an average of just 106ppl on May 21, 2020, on the back of oil falling to $13.21 a barrel at the beginning of the pandemic. Petrol last rocketed by this amount over a 12-month period in May 2010.

RAC fuel spokesman Simon Williams: “We’ve now witnessed the biggest petrol price rise in any 12-month period since May 2010 when unleaded rocketed from 99p a year earlier to 121p.

“As always, the future of fuel prices is hard to predict more than a few weeks in advance and even more so now as the pandemic appears to have altered the dynamics of fuel retailing, with the supermarkets having an even greater stranglehold on the market.”

Buying fuel at a forecourt run by one of the four major supermarket chains will currently save drivers around 4p a litre with the average price of petrol standing at 124.83ppl and diesel 127.36ppl.

The RAC says they are now responsible for selling 60% of all the fuel in the UK.

Filling up on the motorway will set drivers back 146.78ppl for petrol and 149.59ppl for diesel after 2p and 1.6p rises in May.

“Looking at the wholesale price of both fuels, in normal circumstances unleaded definitely shouldn’t be continuing to rise with the numbers actually pointing to the potential for a 2p reduction,” continued Williams. “And diesel is currently 4p too expensive which suggests retailers are using the saving in the wholesale price to help make up for lower fuel sales over the last year.”

The RAC is urging retailers not to take advantage of drivers and “fairly reflect” what is happening with wholesale prices on the country’s forecourts.

Williams added: “Drivers’ fuel price fate depends on what happens with global oil production and demand. Oil producers had curbed supply due to lower demand but have been releasing more product as the travel recovery continues.”