Marks & Spencer plans to be carbon neutral by 2012

Each previously-free plastic bag will cost 5p as part of a pilot scheme being trialled in Cornwall, Devon, Dorset, Somerset and Gloucestershire.

The company aims to cut the number of bags used and money raised by selling the carriers will go to the charity Groundwork UK.

A pilot scheme in Northern Ireland saw a 66% cut in bags used in 16 weeks.

Carbon plans

Sarah Miller, M&S general manager in the South West, said: "Since we announced our intention to trial charging for carriers in the region, feedback has been very positive.

"Customers have been telling us that they are ready to break the habit of using too many bags.

"We hope that the trial will encourage us all to think about the number of carrier bags we are using and make the effort to reduce, reuse and recycle whenever we can."

The store is charging 10p for its "Bag for Life", which will be replaced free of charge when it wears out.

Bags will still be given free of charge with clothes purchases.