Business travel is under environmental scrutiny, and top executives are reassessing how or whether they will travel to do business.

John Sauven, executive director of environmental campaigners Greenpeace, says: "Companies like Sky and Marks and Spencer are beginning to deal with the low-hanging fruit of using low emission vehicles, video conferencing and using trains where possible. But in terms of where we need to get to in cutting CO 2 emissions in the next 100 months, far more radical measures need to be taken.