Up to 5,000 free meals are to be given away in Trafalgar Square today as campaigners attempt to highlight the issue of wasted food.

The ingredients will be six tonnes of irregular shaped fruit and vegetables, donated by farmers, which were thought unsuitable for sale by supermarkets, despite being perfectly edible.

The items would have otherwise been sent to landfill, but have been turned into soups, smoothies and curries for today's giveaway.

Author Tristram Stuart, who organised the event, said he hoped fewer people would discard fresh products as a result of the campaign.

"Feeding the Five Thousand is a wonderful partnership, including food companies, farmers and charities," he added.

"The aim of our lunchtime feast is to highlight how food waste can be avoided by putting food to good use - by feeding people."

About 8.3 million tonnes of food is thrown away each year, enough to fill 4,700 Olympic-sized swimming pools, according to figures from the government's anti-waste arm, Wrap.