Suddenly every British political leader wants to be green. David Cameron, yesterday announced a new set of “environmental taxes” intended to curb air travel.

In retaliation, Gordon Brown, the Chancellor will call today for a “new world order” to address climate change and tomorrow he joins Tony Blair in publishing the Government’s strategy for reducing carbon emissions.

The Conservatives yesterday announced “pay as you burn” plans to relate air taxes to carbon emissions. They are considering introducing a “green air miles allowance”, with people taxed on the distance they travel. Individuals would be entitled to just one short-haul flight a year tax-free, with additional flights attracting progressively higher taxes.

The Government will publish the government’s Climate Change Bill tomorrow. The principle is radical – it will make the UK the first nation to have a legal framework for managing carbon emissions. It will put into law a target to cut carbon emissions by 60 per cent, compared with 1990, with annual reports to Parliament detailing progress and five-year “milestones” to measure success. The Bill will also establish an independent body to monitor work on cutting CO2 and improve the reporting of progress.

A Liberal Democrat spokesman said: “Unlike the other parties, we have a green thread that runs through all our policies. “We have been campaigning on the environment for a long time and Labour and the Tories are trying to catch up. But it’s about having a genuine commitment, rather than making a speech here and there.”

Despite all the green rhetoric, Tony Juniper from Friends of the Earth asks are the targets ambitious enough? “So far all parties have promised a 60 per cent cut by 2050 – yet the latest science shows this isn’t enough if the UK is to play its part in keeping down global temperatures. This is particularly the case if the Bill fails to take into account emissions from international shipping and aviation”.

He also points out that: “This Government has a great record of setting targets, but a terrible one for meeting them. Despite three manifesto promises for a 20 per cent cut in CO2 by 2010, emissions have risen since 1997”.