One of the UK's leading petrol forecourt operators has stoked up the row about soaring petrol prices by accusing the big four supermarkets of profiteering.
Ascona Group chief executive Darren Briggs told the Telegraph that Tesco PLC (LSE:TSCO), J Sainsbury PLC (LSE:SBRY), Wm Morrison Supermarkets and Asda have dragged their feet over implementing the government's fuel duty cut.
Briggs added that supermarkets pay wholesale prices up to three weeks in arrears for their fuel, whereas independents pay the previous week's average price or in a quarter of cases the spot price on the day.
He said he supports a competition inquiry into forecourt pricing, which was announced by the Competition and Markets Authority on a "short and focused" basis following Business Secretary Kwasi Kwarteng's intervention yesterday.
Asda, Tesco, Sainsbury's, and Morrisons dominate the UK fuel market, and sell more than 43% of fuel by volume, but own less than one in five sites.
Brigg's Ascona operates 59 locations across the UK, making it the seventh-largest forecourt operator.
Many forecourt operators are criticised for quickly raising prices when wholesale prices rise and being slow to reduce them when they drop, but Briggs defended that practice saying independents have to do that to overcome the three-week advantage of their supermarket rivals.
Asda said it is the "price leader" and has passed on fuel duty cuts before anyone else.