The average price of diesel shot up by more than 10p a litre in October – the third biggest monthly increase on record.

The gap between petrol and diesel prices is now at a record 24p a litre

A litre of diesel went from 180.37p to 190.51p, adding more than £5 to a tank, RAC data has revealed. It now costs £104.78 to fill up a 55-litre diesel car.

The rise was beaten only by the increases seen in March and June this year when diesel prices rocketed by 22p and 16p respectively, prompting the new all-time high of 199.09p (25 June).

In contrast, the price of petrol last month ‘only’ increased by 4p (3.71p) a litre, from 162.67p to 166.38p, which means a full tank costs £2 more at £91.51.

As a result, October also saw the gap between the forecourt prices of diesel and unleaded reach an all-time high of 24p a litre.

The price hikes began at the start of October when oil producer group OPEC+ agreed to cut production by two million barrels a day. The barrel price subsequently shot up 7% from $88.86 to $94.83, hitting a high of $97 on 27 October. This combined with the weaker pound made wholesale petrol and diesel – which is traded in dollars – more expensive.

The average price of diesel at the big four supermarkets jumped 9p last month, from 178.51p to 187.54p. But unleaded went up 4p from 161.31p to 165.36p – and supermarkets are currently only a penny cheaper for petrol than the UK average. Diesel, however, is 3p a litre than the average when bought at a supermarket.

Motorway petrol increased nearly 8p from 182.83p to 190.48p while diesel rocketed by 12p from 192.74p to 204.24p.

The RAC warned that the average price of a litre could head back to the previous record of 199.09p, bringing the cost of a full tank to more than £109.

But fuel spokesman Simon Williams said analysis of the wholesale market indicated that the diesel price should stabilise.

And he added that petrol drivers should actually see forecourt prices start to drop slightly, as the wholesale cost of unleaded appears to have peaked – at least for the time being – in mid-October.

“We recommend drivers keep an eye on the UK averages on the RAC Fuel Watch website and aim to fill up as far below those prices as possible,” he continued. “The cheapest place to fill up, for those fortunate enough to have membership, is Costco where a litre of petrol costs an average of 154p and diesel 176p – 12p and 14p lower than the UK averages.

“It’s interesting to see just how low fuel can be sold even at a time of $90 oil and a weak pound. Clearly, Costco’s margins are low, but they must surely still be making a profit.”