ENVIRONMENTALLY-friendly "green" carrier bags created from the same starch used to make tapioca pudding are being tested in the North-East.

The bags are available in only three of Sainsbury's supermarkets - two in London and at the Arnison Centre store on the outskirts of Durham City.

But the store chain hopes to introduce them in other locations if they prove popular with customers. Shoppers will be encouraged to re-use the biodegradable bags and compost them when they are worn out.

Normal plastic bags can remain in landfills for dozens of years without breaking down, and release harmful chemicals into the earth.

The tapioca bags break down into the common earth elements carbon, oxygen and hydrogen.

Environmentalists have called on the Government to introduce a tax on plastic bags to discourage their use.

The stores participating in the launch are in Islington, north London, Ladbroke Grove, west London, and Durham.

Sainsbury's packaging innovations manager, Terry Robins, said: "We think customers will love this bag.

"It's as strong and durable as a conventional plastic bag, but is far better for the environment. It biodegrades naturally and leaves no harmful residue."

A Durham County Council spokeswoman said: "It is something we obviously welcome and it supports our scheme to reduce the number of plastic bags in civic waste sites.

"We are pleased that Sainsbury's have made this move and we hope that other supermarkets will start taking up their own schemes.''