Eurostar undertakes it inaugural journey from the new St Pancras International station this morning, amid promises that the new high-speed continental rail link will boast a lower carbon footprint than journeys taken from its previous home at Waterloo.

A spokeswoman for Eurostar said it was too early to determine how significant the carbon savings would be, but insisted that the extension of the high-speed line into central London meant journeys to Paris and Brussels would be both 20 minutes faster and more efficient.

"The new line is now high-speed all the way to Paris and Brussels, so once the train gets up to speed it can just cruise and doesn’t have to accelerate and decelerate, which consumes more energy," she explained.

This morning's journey will also be carbon neutral, according to Eurostar, which has pledged to offset unavoidable emissions from the new link. Speaking earlier this year, chief executive Richard Brown said the company would offset emissions without increasing ticket prices for customers. "Unlike other transport operators, who ask passengers to volunteer to offset CO2 emissions at their own expense, we will bear the cost of making every journey carbon neutral, " he explained.

Eurostar already boasts that the train generates 10-times less CO2 per passenger than comparable flights to Brussels and Paris, and earlier this year committed to cut its carbon footprint by a further 25 per cent by 2012 through its Tread Lightly initiative.

The strategy commits the company to reducing its environmental impact through adoption of sustainable sourcing policies, more energy efficient on-board technologies, improved train capacity and enhanced recycling and waste reduction measures.

The company insists its green credentials are at least partly responsible for a recent improvement in the service's market share. "There is no doubt it is a factor, particularly for corporate clients who are now very aware of their carbon footprint," said the spokeswoman. "For short-haul journeys they understand we are a greener alternative."

She added that leisure customers were also citing environmental considerations as a major factor in their choice of Eurostar. "We've seen a 30 per cent increase in long-haul journeys to the south of France, Germany and the Netherlands, and that is very much down to people deciding to select a more environmentally friendly travel option," she said.