A supermarket's plan to encourage shoppers to share taxis to out-of-town stores in order to reduce carbon emissions has annoyed retailers who maintain shopping locally is a more efficent option.

The Tesco Carbon Voyage scheme will enable shoppers to book journeys online, by phone or by text message. They will be matched with others living nearby and picked up and dropped off by minicab.

Tesco group technology and architecture director Mike Yorwerth said he was confident shoppers would see the benefits. "They extend beyond money saved to making a contribution to a greener world," he said.

James Bielby of the FWD, which is preparing for this year's Walk & Shop Day on September 2, rejected the multiple's claim. He said: "It would be far more environmentally friendly, as well as cheaper, for people to simply walk to their local shops."

Ralf Patel of The Look In store in Woodmansterne, Surrey added: "Green schemes are to be applauded, but one minicab wouldn't be large enough for two or three people plus their weekly shopping."