The amount of good food Britons throw away unnecessarily is at record levels, according to a study published yesterday, costing the economy £10 billion a year.

More than half of the 6.7 million tons of food that households throw away annually is still edible, the study from the Waste and Resources Action Programme (WRAP) revealed.

About £1 billion worth of wasted food is still "in date", the The Food We Waste report concluded, while about £6 billion of food was bought but left untouched.

An average household discards about £420 worth of unused food a year, the government-backed study said, while for families with more children that rises to over £600.

The overall impact on the British economy is over £2 billion more than previously estimated, the researchers from the waste-fighting organisation said.

They calculated that stopping good food waste could reduce annual carbon dioxide emissions by 18 million tonnes. This was same effect as taking one in five cars off British roads, it added.

In what the report's authors said was one of the most comprehensive studies of its kind undertaken in the world, almost 3,000 households were interviewed. The waste from more than 2,100 of those households was also analysed. The study revealed that every day about 1.3 million unopened yoghurt pots, 5,500 whole chickens and 440,000 ready meals are thrown away in the UK.

The amount of binned food would fill London's Wembley Stadium eight times over, it said.

WRAP chief executive officer, Liz Goodwin, described the findings as shocking. "Food waste has a significant environmental impact," she said in a statement.