Unilever, the food giant behind Marmite and Hellmann’s mayonnaise, has increased prices by nearly 10pc as Britain’s competition regulator investigates whether shoppers are being overcharged for groceries.

The FTSE 100 company, which also owns brands such as Magnum, Ben & Jerry’s and Dove, revealed a surge in profits during the first half of the year after underlying price growth jumped 9.4pc.

Price rises boosted the company’s income by nearly a tenth between January and the end of June, despite sales volumes falling slightly. Net profits jumped by more than a fifth to €3.9bn (£3.4bn).

The jump in profits and prices come as Britain’s competition prepares to investigate whether consumer goods companies are overcharging people.

The Competition and Markets Authority (CMA) last week said it would investigate big brand-owners such as Heinz and Unilever to examine if shoppers were getting a raw deal at the tills.

The new phase came after the CMA said its initial investigation found no evidence of profiteering by supermarkets, despite concerns about so-called “greedflation”. 

The regulator said it would “look in further detail at metrics of financial performance of branded and own-label suppliers as part of the next phase of our groceries work”.

On Tuesday, Unilever said it believed Britain had “passed peak inflation”, adding that its price rises in the first half of the year were lower than its 13pc rises at the end of 2022. 

The company said: “We continue to expect a modest improvement in underlying operating margin for the full year, reflecting higher gross margin and increased investment behind our brands.”