Tesco and Marks & Spencer are amongst a group of eight of the UK's biggest businesses, which has embarked on a major corporate social responsibility scheme to help cut carbon dioxide (CO2) emissions.
The "We're in this Together" campaign, spearheaded by independent body The Climate Group aims to reduce CO2 emissions by 25 million tonnes in the next three years.
All eight participating business revealed new projects to assist consumers in cutting their carbon footprints at the launch of "We're in this Together" in London today.
Speaking at the launch, Prime Minister Tony Blair said: "This takes what is a huge public concern about the environment and shows how there can be practical solutions in people's everyday lives. The solution has to be global and comprehensive but individuals want to feel that they can also be a part of it."
Tesco has given itself a target of selling 10m energy-saving light bulbs in the coming year ¬- up from 2m last year. It will double shelf-space and halve prices to chase that goal. M&S is encouraging its customers to lower their washing temperature to 30°C.
Dr Steve Howard, chief executive of The Climate Group, said: "Today marks an unprecedented commitment from some of the UK's favourite brands to help their customers tackle climate change."
The other six companies involved are BSkyB, B&Q, Barclaycard, British Gas, O2 and Royal & SunAlliance (RSA).
