SHOPPERS in supermarkets across Bolton are facing long-term food price increases after stores said the recent heatwave has led to poor crop harvests in the UK and Europe.

Retailers and manufacturers are passing on higher costs from low yields of fruit and wheat, and rising global prices of items such as coffee and orange juice.

Some food prices in supermarkets have risen by as much as 21 per cent since May.

But traders at Bolton's Ashburner Street market claimed the price rises are unnecessary.

They said food shortage claims were overblown, and supermarkets just wanted to raise prices in the face of higher fuel costs.

According to the British Retail Consortium, the retailers trade body, food prices in shops rose for the third successive month in July.

Throughout July, meat prices increased by 3.1 per cent, vegetable prices rose by 4.7 per cent, while milk, cheese and eggs jumped by 2.3 per cent.

Tesco, the largest food retailer, said increased food costs arising from poor harvests would be passed on to consumers.

A spokesman said: "When wholesale costs go up, some prices will follow to reflect that change, but we do all we can to keep prices as low as possible."

A spokesman for Asda said: "Despite oil prices nearly doubling in the last 12 months, we have done our best to keep our prices as low as ever", while Sainsbury said: "We continue to invest in lower prices."

But a spokesman for Bates Brothers, which sells fruit and vegetables at Ashburner Street market, said the company had not experienced any supply shortages.

"We haven't seen any shortages of anything. In fact, there was not enough room for all the produce in the warehouse this morning," he said. "It is just an excuse by the supermarkets to put prices up."

Another trader, whose stall sells cheese and salad vegetables, said: "I have seen slight problems with some of the salad vegetables such as web lettuce, which suffered because of the heatwave, but it has righted itself now.

"The supermarkets have been hit by higher fuel prices and they are trying to recoup it by putting prices up. Using supposed food shortages as an excuse."

Analysts believe the latest round of price rises could signal the end of aggressive competition among supermarkets as retailers try to restore profit margins.

Jonathan Pritchard, an analyst at stockbrokers Oriel Securities, said: "Price competition amongst supermarkets has not been as fierce in the last three months."

The National Association of Master Bakers expects bread to rise in price by 2p to 4p a loaf.

The association said bad weather has led to a poor wheat crop which, coupled with rising energy costs, means the price of flour is about to rise by between 15 and 20 per cent.