Ministers are preparing concessions to head off a Labour rebellion over plans to exclude aviation and shipping from new targets to cut Britain's carbon emissions.
Ed Miliband, the Energy and Climate Change Secretary, is working on amendments to the Climate Change Bill which pledges that the UK will reduce emissions by 80 per cent before the middle of the century.
But emissions from international shipping and air traffic were originally excluded from the calculations, prompting MPs to stage a rebellion. Mr Miliband is understood to be working on a form of words to ensure that the key areas of aviation and shipping can be included on the face of the Bill when it is debated by MPs next week.
He is also preparing to strengthen the Bill – which introduces the world's toughest legally binding targets for cutting emissions – to force most companies to declare their annual carbon emissions as part of efforts to drive down energy consumption.
Fifty-six Labour backbenchers are threatening to defy the Government if ministers do not include the two industries in the Bill when it is debated on Tuesday. The group – enough to overwhelm Gordon Brown's majority of 62 – have signed a rebel amendment designed to ensure aviation and shipping are included on the face of the Bill.
Ministers are understood to be working on a compromise to meet the concerns of Labour MPs but are anxious not to commit the Government to a binding target to cut emissions from air and sea travel when there is no international agreement on how to measure pollution from the two industries.
One senior government source said: "We want to make sure what we do is something that works. We don't want to write something into the Bill which makes it impossible to implement."
Nigel Griffiths, the former minister who tabled the rebel amendment, said: "I'm confident the Government will make concessions. I have had very fruitful discussions with Ed Miliband and [the climate change minister] Joan Ruddock who have left me in no doubt of their concern to ensure that every possible source of carbon dioxide emissions will be included."
Environmentalists have been pressing ministers not to exclude aviation and shipping from targets to cut carbon emissions, arguing that if international agreements cannot be reached, domestic greenhouse gas targets should be strengthened to compensate for the impact of planes and ships.
In January, a Commons motion calling for aviation and shipping to be included in CO2 targets was signed by more than 250 MPs, including 164 Labour MPs. A similar motion tabled earlier this month has been signed by 74 Labour MPs. Martyn Williams, Friends of the Earth's parliamentary campaigner, said: "If ministers get this right they will have introduced a world-class climate change bill we can all be proud of."Reuse content