'Green' supermarkets clocking up food miles

But when it comes to their Christmas food, it seems to be a different story. Instead of locally produced, fresh produce, stores are selling foods from Israel, Madagascar and Alaska.

A glossy brochure produced by Waitrose offers New Zealand clams which will have clocked up nearly 12,000 food miles by the time they reach the dining table.

Marks & Spencer's brochure advertises a fruits de mer platter of Madagascan prawns, Canadian lobster and snow crab claws which will have travelled a total of 13,382 miles.

Waitrose prides itself on its green credentials and was the first supermarket chain to offer a 10p hardwearing shopping bag. It also runs a food miles education course, visiting schools and teaching pupils where its produce comes from.

The firm's recent corporate social responsibility report stated: "To limit our impacts on the environment and our local communities, we avoid unnecessary mileage and use the cleanest technology available."

Marks & Spencer uses the slogan: "Plan A - because there is no Plan B". A statement on its website says: "Plan A is our five-year, 100-point plan to tackle some of the biggest challenges facing our business and our world. It will see us working with our customers and suppliers to combat climate change, reduce waste, safeguard natural resources, trade ethically and build a healthier nation."

A Waitrose spokeswoman said it was not in the company's interest to transport food unnecessarily. "Our buyers work hard to source British ingredients," she said. "Wherever there's a sustainable option from our own shores we will choose it.

"However, we don't feel the ethical sourcing argument can simply come down to miles travelled." For example, Madagascan crevettes came from a community which used the income to build a school and hospital, she said.

A Marks & Spencer spokeswoman said it sourced as much food as possible from the UK and Europe. She added: "We are stocking Madagascan and Honduran prawns, however these are processed at source, frozen and shipped to the UK so are not airfreighted. We have topped the Marine Conservation Society supermarket league for the last two years for our sustainable fish-sourcing."