Sainsbury’s is testing a new app to help shoppers track how much food they throw away.

The ‘Winnow’ app is based on technology used to monitor food waste in restaurant kitchens.

The app is being trialled by customers, including a group of three MPs, before Sainsbury’s looks to roll it out across the country, the Daily Mail reported. 

It is designed to help families to adjust their shopping as part of a new war on waste.

Households reportedly waste around seven million tonnes of food a year, costing an estimated £12.5bn.

The app will calculate how much money has been wasted on things not eaten and over time works out if certain items are frequently bought but never used.

The app is updated with the latest prices of Sainsbury’s products and gives a weekly report on the financial cost of the waste and information on how it could be reduced. 

Sainsbury’s head of sustainability Paul Crewe said: “When it comes to food waste we’re a nation in denial, frequently underestimating what we throw away.

“Thankfully this trial can really hammer home the amount of food going in the bin, which is the first step to making a change. We’re all excited to see the results.”