One of Britain’s biggest dairies has given warning that it may need to raise the price of a pint of milk in a move that will trigger fresh fears over inflationary pressures in the economy.

Robert Wiseman said today that plastic and oil costs had increased 8 per cent in January to a record high while diesel prices were 12 per cent higher than they were last summer.

The company was one of the groups fined by the Office of Fair Trading in December over price-fixing six years ago and last hit consumers with a price rise in the autumn.

The Glasgow-based group said: “If these costs persist, they are likely to require an increase in our selling prices to maintain operating margins.”

The warning came despite signs that commodity milk prices paid by the dairies were beginning to fall in a slump that could hit farmers across the UK.

The group processes more than 1.3 billion litres of milk a year and controls about 20 per cent of the UK market. It introduced lighter milk bottle tops last year in a bid to combat the rising cost of plastic.

Dairy Crest, home to Cathedral City and Clover, said yesterday that it had managed to pass on a 35 per cent rise in milk prices to consumers in the past year.

Robert Wiseman signalled today that despite the rising cost pressure across its business, it was still trading in line with expectations. Sales over the ten months to January 26 hit internal forecasts.

The group added that it was holding farm gate prices firm next month despite the softness in the dairy commodity market.

It said: “The challenges presented by rising costs and volatile commodity pricing are familiar ones, which we expect to be satisfactorily dealt with in the period ahead.”

Its comments mark the latest in a line of warnings from the food processor, catering and retail sector.

McDonald’s said this month that it may need to push up the price of some of its burgers this year, given cost pressure across the fast-food chain.

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