SHOPPERS queued for hours to buy a designer shopping bag emblazoned with the words "I'm not a plastic bag". It was sold to them in - you guessed it - a plastic bag.

In the latest eco-friendly initiative by a supermarket chain, branches of Sainsbury's were selling a reuseable shopping bag designed by Anya Hindmarch.

Two Bournemouth University students camped outside Sainsbury's at Castlepoint from midnight to ensure they got their hands on the £5 bags.

Matthew Waite, first in the queue, said: "It was quite funny because these are supposed to be environmentally friendly shopping bags but Sainsbury's sold them to us in plastic bags so actually more plastic bags were used by us buying the bags than if we had not bought them."

A Sainsbury's spokesman aid: "Selling the Anya Hindmarch bag is just one of the ways that Sainsbury's is trying to reduce the use of plastic bags.

"The company is urging that customers keep and reuse these on future shopping trips, thereby reducing the amount of disposable carriers bags in the future."

Tomorrow, Sainsbury's will give customers tougher reuseable bags in place of disposable carrier bags. When these wear out they will be replaced for free.

Waitrose is to pilot a similar scheme in Saffron Walden. A spokesman said: "A survey showed 90 per cent of our customers in favour of the policy."

On Monday, Tesco announced that it was halving the price of energy-saving light bulbs.

Asda is offering vouchers for schools if customers refuse plastic bags and composting waste from the Canford Heath and Poole stores.

A spokesman for Asda said: "There has been a change in focus on environmental issues over the last 12 to 18 months but a lot of green initiatives have been running for five years or so because they save the company money. Asda spends £25 million a year on carrier bags which all end up in landfill sites. Taking bags is a habit we need customers to break."

The store offers incentives to persuade customers not to take carrier bags or use reuseable ones.

The spokesman added: "Every bag costs us 2p so if customers are not taking them we will have more money to invest in other things. This could be making energy-saving light bulbs cheaper and so the virtuous circle can continue."

Angela Pooley, co-ordinator for East Dorset Friends of the Earth, said: "There is a degree of greenwash but supermarkets are doing a lot in terms of recycling and that kind of thing. But there is still much more they could be doing."

She believes that as consumers everyone has the power to influence supermarkets to become more environmentally friendly.

Miss Pooley said: "Should we really be buying strawberries in the middle of winter when they have been flown half the way across the world?"

She added: "You should use supermarkets as little as possible. Shopping locally from small local suppliers is always going to be more environmentally sound but this is perhaps unrealistic."

She said that shopping in places like farmers' markets is not always as expensive as people expect.

Miss Pooley said: "Green has gone beyond being trendy and has become much more mainstream.

"However, the decisions that consumers have to make have become harder. You used just to be able to take your bottles to the bottle bank and use unleaded petrol but now you have to make much more difficult decisions about changing your lifestyle."