Two years ago the Greening Supermarkets Report was none too complimentary about the multiples. While the industry was waking up to the green agenda, no single retailer could genuinely claim to be green in the five categories explored by the National Consumer Council report. In two weeks time a review of that report is due to be published and, given the raft of measures, new initiatives and heavy PR spend devoted to the cause, expected to be much more favourable.

From reducing packaging to calculating carbon footprints, redrawing supply networks to simply cutting down plastic bag use, green pledges now form a major plank of supermarket strategies. Just this week, Sainsbury's announced its Different Values campaign to shout about its green initiatives. Everyone is at it, as our table of green pledges and progress (next page) shows.

"We have seen a significant change in performance in the past two years," says Dr Sally Uren, director of sustainability charity Forum for the Future's Business Programme. "At that point we had the germs of good practice but there was some way to go before 'green' became mainstream. Green issues weren't flowing through; they are now."

Uren, who has been involved in the Greening Review, has been impressed in particular by the strides made to reduce unnecessary food miles. Backhauling has been improved, double-decker trailers with increased capacity have been introduced, and there has been a concerted effort to switch deliveries to rail. The improved distribution networks mean, for example, that Sainsbury's expects its fleet and suppliers to slash five million kms out of its total distance travelled by 2010; Tesco's vehicles are now travelling eight million miles fewer annually; Morrisons expects to cut 6% of its road miles per pallet of stock; and Asda has reduced its fleet mileage by 16 million - 4.5 million alone by moving more of its freight to rail.

Store performance has also seen a noticeable improvement. Says Uren: "If a company is serious about becoming greener you have to look at their energy consumption in-store, whether they are refitting to high environmental standards, and whether new buildings are making the most of green technology." On the whole they are. Tesco has built four model environmental stores, with its Shrewsbury store working to a 60% smaller carbon footprint than a conventional store, while Morrisons' new Cardiff store - built on a former domestic refuse tip - is built with 80%-recyclable framework, eight-metre-high glazed walls for increased natural light, and a nine metre-deep canopy over the checkout mall that reduces the need for air conditioning by preventing heat gain.

Uren, who has worked with supermarkets to improve their sustainability, has noted a concerted effort from the multiples to work through their supply chains to find environmental improvements, but says there is still a lot of work to be done. "Retailers and manufacturers have to collaborate more on key issues such as packaging and transport," she says.

Packaging is an issue where Uren has been left "underwhelmed". "The industry still appears nervous about consumer perception if packaging is removed. There are some fantastic ideas out there but movement has been slow. Retailers need to educate customers about the need to reduce packaging so they are not put off."

Indeed - with Tesco calculating that it produces 2.3 million tonnes of CO2, equating to just 2% of the emissions from the food and drink industry. "The biggest impact the retail sector has is the products it sells," says Beverley Parrish, associate director at WSP Environmental. "You can only do so much through saving energy in stores. Retailers have to reduce the impact of their suppliers by helping them improve." Earlier this month, the Carbon Trust announced that it was working with nine new partners, including Coca-Cola, Müller and Kimberly-Clark fo further its work in this area, following successful trials with Walkers Crisps, Boots and Innocent Drinks.

But retailers should think hard about choice editing, says Uren. "They need to work with environmental experts to decide the impact of certain products . It will be easier to make decisions on some lines than others - patio heaters are this year's fur coat and should not be sold. And better signposting of green products will help shoppers make the right decisions."

The current crackdown on carrier bag use, spurred on by a government target of reducing their environmental impact by a quarter by 2008, can play a key part in persuading consumers to go green. It is already having an effect. There was a stampede for the Anna Hindmarch 'I'm not a plastic bag' creation sold at Sainsbury's this spring, and the clamour for reusable bags is growing across the board. The Co-operative Group now sells 3.5 million Bags For Life annually and has launched a cotton carrier bag, which has been used to support the growing number of "plastic bag-free town" campaigns in places such as Modbury in Devon and Hebden Bridge in Yorkshire. "Cutting down on carrier bag use is the final piece of the jigsaw to make shoppers think about the wider green issues ," says Uren.

But the initiatives are not enough for some campaigners. "If supermarkets really cared about this issue they would be lobbying the European Commission to substantially increase the recycling targets in the Packaging Directive," says Sandra Bell, supermarkets campaigner, Friends of the Earth. "The measures that supermarkets are taking do not go far enough. They should be phasing out the one-use plastic bag completely. Even if Tesco meets its target for reducing the amount of plastic bags it hands out, it will still be giving out three billion bags a year."

Environmental campaigners do have praise for some retailer action, particularly M&S and its Plan A strategy. The 100-point plan includes becoming carbon-neutral and sending no waste to landfill by 2012. "M&S is clear and unambiguous and sets the challenges around the right issues," says Parrish, who has been impressed by the targets it has set, the tracking process it is implementing, and the way it is communicating its message to the public. "The best strategies demonstrate how specific objectives can be achieved."

M&S also topped research by the CSR Network into green business strategies of UK grocers . "It's one thing setting targets and another to accurately measure and publish them," says Todd Cort, principal consultant at CSR Network. "M&S has integrated its environmental intentions within the core business strategy, and will invite external bodies to examine progress."

It is this shift in boardroom attitudes that is the most significant factor in moving the green agenda forward. "As a sector, the supermarkets are taking environmental issues seriously and have incorporated their social responsibility departments within the core framework of the business," says Uren.

But if they want to thrive, not just survive, the multiples need to be aware of the future green issues heading their way. Reducing water consumption and being prepared for the Reach Directive, a register of chemicals found in food manufacturing, are thought to be the most pressing issues.

"No-one is dealing adequately with reducing water consumption," says Parrish. "As it becomes an even more precious resource as climate change increases, water saving solutions will be vital. They also need to be working now on preparing for the impact of the Reach Directive, the most complex piece of legislation to be introduced in Europe. Consumers haven't got a clue about it, so retailers are doing nothing. They need to, and quickly." nMaking savings in CO2 emissions

34 The equivalent number of trips to the moon and back that have been cut from Asda's total annual road miles. A series of initiatives have reduced the fleet's mileage by 16 million a year.The denim wine carrier

120 The tonnes of waste fabric that would be diverted from landfill if a wine carrier trial at M&S is rolled out across all stores. It is made from recycled denim offcuts which are processed to form cardboard-like material.