Four leading supermarkets will launch a prototype of the industry’s first harmonised front-of-pack environmental label, in what has been billed as a major step forward in transparency over the impact of products.

Co-op, Morrisons, Sainsbury’s and Tesco will pilot the new label over the summer, with plans for a wider industry rollout as early as next year.

Although the exact format of the label is still being finalised, it is understood to combine an eco-scoring system with colour-coded elements like the front-of-pack health labelling already used by many retailers and suppliers.

IGD is spearheading the move, backed by Defra and Wrap. It said the move was vital to prevent confusion among consumers baffled by the emergence of competing eco-labels in recent months, and to establish an accepted system of measuring environmental impact.

The first public tests of the new label are set to be carried out using separate panels of shoppers from each of the four retailers. They will use virtual reality technology to carry out virtual shopping exercises, which will be set up to find out the impact of the new system on sales.

Experts from the supermarkets have come up with six designs, with one to be chosen in the next few weeks. It is understood the new system is aimed at being front-of-pack, with the UK free to adopt its own labelling system after Brexit.

The scoring system will be based on research IGD has commissioned on metrics including the impact on climate change, land use, water use and water quality.

IGD said it was vital to enable consumers to make more informed choices at point of sale, based on credible data and consistent methods for environmental footprinting.

The body is also stressing the need for a harmonised system, with the emergence of rival environmental labeling schemes sparking fears of mass consumer confusion.

In June last year, companies including Nestlé , M&S, the Co-op and Sainsbury’s were involved in the launch of Foundation Earth, an alternative front-of-pack eco-scoring system measuring carbon emissions, water usage and impact on biodiversity loss.

It has since signed up suppliers including the likes of Cranswick, Finnebrogue Artisan, Mash Direct, Mighty, White’s Oats and Natco.