Study by Which? looked at greenhouse gas emissions as well as plastic waste and food waste.
Waitrose and Lidl are the most sustainable supermarkets, according to a Which?’s eco-friendly grocer ranking.
Iceland finished last, according to the research, which tracked supermarket policies on: plastic waste and food waste, which shoppers have reported are the biggest issues for them; and greenhouse gas emissions, which most experts say poses the greatest environmental threat.
In its first such ranking, the consumer magazine pointed out that supermarkets respond to customer demand, so if shoppers make eco-friendly choices and demand sustainable options, this can influence shops to improve.