High grocery prices look likely to remain for the next decade, according to top executives from two of the world’s largest consumer goods groups.

They say the costs of food and other items are unlikely to fall significantly, even though some commodity prices have slipped back recently.

“We have been through a period of low costs. I don’t think we are going to see those again,” said Alan Lafley, chief executive of Procter & Gamble, whose products include Pampers nappies and Ariel washing powder. “Energy and commodity costs will be higher in the first two decades of the 21st century than in the 1980s or 1990s.”

Lafley said demand was being driven by growth in China and India, which could induce further price rises. “To the extent that price rises are driven by demand, they are going to be higher, yes,” he said.

According to the British Retail Consortium, food inflation stood at 10% for the past 12 months, although it slowed to its lowest rate in five months during August. A survey by Verdict Research, the retail consultancy, last week showed that the cost of a typical supermarket trolley of food has risen by 8.3% since the beginning of the year.

Some items, such as basmati rice, pasta sauce and chicken have soared by more than 40%. The price of meat and fish has risen by more than 20% during 2008, according to Verdict, and the price of fresh fruit and vegetables by nearly 15%.

A senior executive at Nestlé, the food producer, also predicts that prices will remain high. “You will not see over the next years commodity prices return to previous levels of even two or three years ago,” said Luis Cantarell, former head of Europe for Nestlé, who is being promoted to run its American business. “There has been a fundamental shift.”

Nestlé, which makes Shredded Wheat, Kit-Kat and Bonio dog food, among other things, has dealt with the increased cost by passing on price rises of up to 15% across its range of 160,000 products, as well as cutting costs within the business.

Other companies are keeping prices the same but reducing the quantity of goods in their packets. Lafley admitted that his firm had been engaged in “size optimisation” — putting fewer Pringles crisps in a can so that it can pass on rising costs without increasing the price.

Independent experts agree with manufacturers that structural changes in the world economy mean that the previous trend of a long-term decline in the cost of food has come to an end.

Professor John Beddington, the prime minister’s chief scientific adviser, said yesterday: “I think we are going to have to expect to have — throughout the world and not just in the UK — higher food prices.”

Although prices may dip on falling commodity costs, said Beddington, the fast rise in world population will maintain an upwards pressure. World population is rising by about 6m a month.

Innovation may offset some of the pressures. Cantarell added: “The set-up of the agricultural world came as a consequence of the first green revolution. Now we need a second green revolution in order to improve quality and address the imbalance between demand and supply. I think this will happen.”

Lafley, who has co-written a book, The Game-Changer, about how business leaders can drive innovation, said: “It will stimulate more innovation as we try to develop more value. A lot of good things are going into using less energy. It is a case of necessity being the mother of innovation.”

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