Supermarket executives have denied making too much money from soaring prices, telling MPs the industry is the “most competitive we have ever been”.
Bosses from Tesco, Sainsbury’s, Asda and Morrisons were grilled over high food and fuel prices.
The supermarkets rejected claims of making excess profits and said they were shielding customers from the full impact of rising costs.
The competition watchdog is looking into the level of food and fuel prices, examining whether not enough competition has meant customers are overpaying.
Supermarket executives were quizzed by MPs on the Business and Trade Committee on Tuesday on why food prices were still rising, despite some falling wholesale costs.
Food prices rose by 14.6% in the year to June, according to the British Retail Consortium (BRC), which represents supermarkets.
That was down from 15.4% in the year to May, but it does not mean prices are falling, just that they are rising at a slower pace.
Higher grocery prices remain a key reason why the overall rate of inflation in the UK remains stubbornly high.