Sir; Tesco seems keen to vaunt its green credentials with its new scheme to reward customers who re-use plastic bags but its efforts are really little more than greenspin.

Even if Tesco meets its target of reducing the number of bags used, it will still be handing out three billion plastic bags every year.

Tesco boasts that these will be degradable - not biodegradable - but this is not an environmentally friendly solution. Most will end up in landfill - where they will not be exposed to the sunlight they need to decompose. When they eventually rot, they will give off methane - contributing to climate change. And because they are still made of plastic they will still depend on oil for their production.

What is more, Tesco's plastic bag waste is just a drop in the ocean compared to the vast quantities of food ­packaging waste that its stores generate.

Until Tesco sets ambitious targets to cut food packaging, it cannot claim to be making a serious commitment to tackling waste.