An unlikely new battleground has emerged in the fight to become the most eco-friendly retailer - the supermarket trolley.

Tesco will take delivery of 165,000 'green' trolleys from manufacturer Clares between now and February 2008 after rigorous testing showed they were as reliable as their less environmentally sound counterparts.

Envirobrite trolleys are made using alkali zinc plating technology that offers an exceptionally shiny finish and a reduced carbon footprint compared with conventional trolleys.

Clares said the new process uses 83% less zinc, and as a result consumes less water and energy and produces less waste.

"Envirobrite offers an exceptionally shiny appearance while ­significantly reducing the environmental impact of trolley production," said Phil Bigland, Clares' group sales and marketing director.

No value has been disclosed for the contract but the trolleys cost £55-£130.