A review by WRAP concludes that around 3.6 million tonnes of UK food surplus and waste occur in primary production every year, worth £1.2 billion.

Agricultural food waste tops 1.6 million tonnes with two million tonnes of surplus – equivalent to seven per cent of total annual UK food harvest.

The review will help drive forward work on the root causes at a key stage in the supply chain, and help more food reach its intended market.

The scope of WRAP’s review covers the moment when a food crop is ready to harvest, or an animal to be slaughtered, and assesses surplus and waste arising from processes such as grading, packing and washing – as well as customer rejections.

WRAP estimates that food waste accounts for 1.6 million tonnes of the total figure, or around three per cent of production with a market value of around £650 million. Sugar beet, potatoes and carrots made up more than half of the overall waste by weight, with the top ten products accounting for 80 per cent of the total weight. When grouped by product type, horticultural crops make up 54 per cent of the total, cereals 30 per cent, livestock eight per cent and milk eight per cent.

A significant factor is also the percentage of a crop that becomes waste. For example, of the top twenty foods listed milk has the highest total production by weight at nearly 15 million tonnes. In this case, 116,000 tonnes of milk waste arose representing 0.8 per cent of total production. While for lettuces, the percentage of waste is nearly 25 per cent of total production (104,000 tonnes).

Surplus food comprises those products that are not sold for human consumption as intended, but which are instead used as livestock feed, redistributed to charities, or may become bio-based materials such as colorants. The amount of surplus food is estimated to be an additional two million tonnes per annum, or four per cent of production with a market value of more than £500 million.

Peter Maddox, director at WRAP said: “This is the most detailed study of food surplus and waste in primary production undertaken for the UK, and a key finding has been the range of waste across all food categories.

"This tells us there is huge potential to reduce the amount of surplus and waste by promoting best practice, and that’s where our work is now focussed. We want to increase redistribution of surplus food as has happened across the retail sector, and I am pleased this will now be much easier through the Food Surplus Network.

“Given the scale and challenge of gathering data from the sector, we are calling on businesses and researchers to share their insights with us through our collaborative data sharing platform. This provides a simple way to share data with WRAP, which can be combined into a living evidence base. This will help bring more clarity to an issue that is happening around the globe.”

Peter Andrews, head of sustainability at the British Retail Consortium, said: “Food waste is a major source of carbon emissions and we support WRAP’s efforts to mitigate it.

"The challenges involved in tackling food waste in farming are vast, but if we are to be serious about these environmental and social challenges of food production and consumption then we can leave no stone unturned. Retailers are working closely with their suppliers to minimise waste, for example by using more accurate prediction of demand, finding ways to use surplus production, and settings clear targets for future improvement.”