Drivers are paying record fuel prices with "heartless" supermarkets charging more at the pumps this Christmas, according to the RAC.
Petrol garages are charging more than last year, even though they are buying the fuel at the same price.
The Government has also cut fuel duty by 5p per litre in the UK until March but drivers are struggling to see the benefits trickle down.
Motoring groups said the findings are "verging on the scandalous" as drivers pay the highest petrol and diesel prices of any Christmas.
The RAC is demanding that garages cut their prices immediately, following recent findings reported by The Times.
It shows how filling up an average tank with petrol costs £4 more than 12 months ago, at £84.
While filling up an average tank with diesel costs £15 more, at £97.
This means that petrol costs 153p per litre, up 7p from last year, and diesel costs 176p, up 27p.
"With the cost-of-living crisis making this one of the toughest Christmases on record, it is even more galling to know drivers are being heartlessly overcharged for fuel, making this the most expensive-ever festive getaway on the roads,” said RAC spokesperson Simon Williams.
"The big four supermarkets, which dominate UK fuel retailing, have robustly refused to significantly lower their forecourt prices to reflect what’s happened."
Despite the hikes, wholesale prices for petrol have not changed, at 106p a litre – the same as last year.
While the wholesale cost of diesel has risen 14p per litre compared to last year.
It is not the first time supermarkets have been urged to cut their fuel prices after being accused by the RAC of "taking advantage" of drivers last month.
The motoring organisation has said several times this year that the UK’s biggest retailers are not lowering their prices despite the dip in wholesale costs.
It means the supermarkets are now often not the cheapest place to get your petrol and diesel, with the RAC claiming that some independent forecourts now have better prices.
Previous analysis shows supermarkets have enjoyed margins of around 15p a litre on both petrol and diesel.
In November, the RAC called for prices to be cut by around 5p a litre to make it fairer for motorists.
It said drivers are paying an “unnecessarily high” average price at the supermarkets .
