Three of the UK's 'big four' supermarkets have been found to be raising fuel prices by nearly three times as much as necessary.

Sainsbury’s, Morrissons and Tesco have been accused of exploiting drivers having all increased prices by an average of 3p per litre in December, despite the wholesale cost of fuel only rising by around a penny.

Only Asda, which added around 1.5p to its prices matched the wholesale increase.

The RAC’s fuel spokesman Simon Williams said that the supermarkets appeared to be trying to protect themselves from a possible drop in income during the latest lockdown. 

December’s increases pushed the average price of unleaded petrol to 116.46p per litre and diesel to 120p per litre. According to the RAC Fuel Watch calculations, the wholesale price changes should have seen drivers paying 113p for petrol and 118 for diesel.

Asda was selling both the cheapest supermarket petrol and diesel at the close of December. A litre of unleaded cost 110.11p a litre and diesel 113.4p. Sainsbury’s was 1.5p dearer for petrol and 1.38p for diesel. Despite this, filling up at a supermarket is still 4p a litre cheaper for unleaded and nearly 4.5p for diesel than at other retailers.

Mr Williams said: “It’s very disappointing to see some of our biggest fuel retailers putting up their prices over and above the increases seen on the wholesale market. There’s a definite feeling that they have been trying to protect themselves for what was to come in terms of further coronavirus restrictions.

“While wholesale prices went up very slightly in December our data shows there should be scope to lower forecourt prices rather than put them up.

"Retailers will no doubt argue that the pandemic is leading to drivers filling up far less so their ‘per litre’ profits are considerably down, and Monday’s announcement of another lockdown will be treated as justification for their decision not to pass savings on at the pumps.

"Unfortunately, those who still need to fill up regularly are having to pay more than they should be as, by our calculations, both fuels should actually come down by 3p a litre in the next fortnight.”

Mr Williams predicted that when lockdown restrictions lift, prices are likely to increase further. He said: “As and when life begins to become more normal as a result of the Covid vaccination programme the price we pay for fuel will inevitably go back up again.

"A year ago, a litre of unleaded set drivers back 127p and diesel 132p, which is 10p and 12p cheaper, respectively, than today.”