Eurostar, which links London with Paris and mainland Europe via the Channel Tunnel, said it would cut CO2 emissions by 25 percent per passenger by 2012 by improving the efficiency of its trains and sourcing power from greener electricity generators. "We do know that a high-speed rail journey is 10 times greener than flying," said Eurostar Chief Executive Richard Brown. "The low-cost airlines phenomenon has come up over the last 10 years. We're looking to attract more passengers to travel with us."

Environmental group Friends of the Earth said it was backing use of Eurostar as a means of cutting UK greenhouse gas emissions without damaging people's travel plans and lifestyles.

Where Eurostar cannot eliminate CO2 emissions, it will invest in carbon offsetting schemes at its own expense, it added. "We will bear the cost of making every journey carbon neutral," said Brown. "We will not charge a penny extra." Brown said Eurostar trains currently generate around 50,000 tonnes of CO2 a year and most of this would be offset from November when the group launches its new high speed link to continental Europe from London's St Pancras station.