The environmental group Greenpeace staged a protest yesterday at Woolworths' London headquarters as part of a campaign to convince the retailer to take inefficient incandescent lightbulbs off the shelves by 2008.

It was timed to coincide with the release of the group's half-yearly financial results.

About 30 volunteers delivered thousands of signatures written on flags and formed a colonnade which staff passed under to reach their offices in Marylebone, while holding a banner reading 'Customers tell Woolworths - shelve old bulbs now'.

Office workers were handed free compact fluorescent (CFL) bulbs as gifts and urged to bring up the topic with their managers.

Greenpeace claims that a recent policy announcement made by Woolworths about the phasing out of old-fashioned incandescent lightbulbs is dangerously weak. While other retailers have committed to remove all such bulbs from stores as soon as this year, Woolworths has just announced a move which would barely comply with the government's own voluntary initiative, which would see the bulbs off the shelves by 2011.

In addition, the cheapest compact fluorescent bulb currently on sale at Woolworths is priced at £2.49, while the retailer recently announced that it would be selling an entire bottle of champagne for £5 - the price of two low-energy lightbulbs.

For each year that British retailers keep selling incandescent lightbulbs, five million tonnes of unnecessary CO2 are released into the atmosphere, Greenpeace said. Put another way, if all UK retailers moved as slowly as Woolworths, the UK would emit 20 million tonnes of CO2 unnecessarily - the equivalent to the yearly output of the entire country of Yemen.

Robin Oakley, a climate campaigner with Greenpeace, said: "We're here to tell Woolworths that their customers want them to move a lot faster. Removing power crazy lightbulbs from the shelves should be a first, quick step on the road towards offering truly sustainable products across the board. Instead, Woolworths are doing the bare minimum, while most of their competitors are going much further."

Woolworths recently changed its policy after a Greenpeace league table, which lists the commitments of all major UK retailers to phasing out inefficient bulbs, gave them a W grade for worst. A recent hurried decision to comply with the 2011 government target still puts them behind Currys (2007), Habitat (2009), Sainsburys (2010) and Asda (2010).

Oakley added: "The scientists are telling us that we have less than ten years left to really drastically reduce our carbon dioxide emissions, but Woolworths are telling us that it takes four of those years to change a lightbulb. If the company really cares about offering their customers value for money they should only be selling CFL bulbs, which save households around £50 every single year."

Woolworths said in a statement: "We are in ongoing discussions with Greenpeace with regard to the sale of lightbulbs. Woolworths sells 5,000 energy efficient lightbulbs a week and has a range of 15 different energy saving options for customers (a quarter of our total range). We wrote to Greenpeace on Thursday to make our position clear and to share with them plans to stop selling incandescent lightbulbs by 2011, phase out energy inefficient lightbulbs gradually in the run up to that date and promote energy saving lightbulbs to our customers. Greenpeace has not responded. We have asked Greenpeace to pass on our comments to its members and update its literature."