The average household throws out one-third of all food bought, wasting £420 each year or £610 for those with children, the Waste and Resources Action Programme (Wrap) said.

The figure is £2 billion higher than previously estimated, the report said. The Government described the figures as "staggering" and "shocking".

Researchers found that more than half the discarded food, worth £6 billion a year, was bought but left untouched.

Each day householders throw out 1.3 million unopened yoghurt pots, 5,500 whole chickens and 440,000 ready meals, according to the report.

It found £1 billion worth of discarded products were still "in date", and that local authorities were spending the same amount each year disposing of food waste.

Most of the wasted food went to landfill sites where it emitted methane, a powerful greenhouse gas. Cutting food waste could limit carbon dioxide emissions by 18 million tons, the report concluded.

Environment minister Joan Ruddock said: "These findings are staggering in their own right, but at a time when global food shortages are in the headlines this kind of wastefulness becomes even more shocking."

Wrap chief executive Liz Goodwin said: "Food waste has a significant environmental impact. This research confirms that it is an issue for us all, whether as consumers, retailers, local or central government.

"What shocked me the most was the cost of our food waste at a time of rising food bills, and generally a tighter pull on our purse strings. It highlights that this is an economic and social issue, as well as about how much we understand the value of our food."