The UK Government’s commitment to tackling climate change is once again under scrutiny after it has emerged that the long-awaited climate change Bill has been downgraded.

The measure will be published next month as a draft Bill for consultation rather than as a fully fledged piece of legislation. Critics claim that it means that David Miliband, the Environment Secretary, had been defeated in his attempt to push through the Bill in this parliamentary session.

Senior ministers have admitted that a Bill introduced towards the end of the session would have to be “carried over” into the 2007-08 session if it was to become law.

Liberal Democrat spokesperson Mr Huhne said: “The climate change Bill will now be presented as merely a draft Bill going for prelegislative scrutiny before a joint committee. The climate change Bill will be postponed to next year at the earliest, and the marine Bill will be even farther down the track”.