LABOUR MPs are threatening to throw Gordon Brown’s flagship Bill to tackle climate change into chaos, in the latest backbench revolt.

Frank Cook (Stockton North), Chris Mullin (Sunderland South), Ronnie Campbell (Blyth Valley) and Jim Cousins (Newcastle Central) are among 56 Labour MPs demanding the Prime Minister beef up his much-hyped legislation to slash carbon emissions by 80 per cent.

The rebels want the rising emissions from both aviation and shipping included in the UK’s greenhouse gas targets – something ministers have refused to do.

They are backing a Friends of the Earth protest that a climate change law leaving out emissions from planes and ships is like “a drink-driving law that doesn’t count whisky”.

Crucially, the 56 rebels are enough to defeat the Prime Minister when the Climate Change Bill goes to a Commons’ vote next Tuesday.

The amendment has been tabled by Edinburgh South MP Nigel Griffiths, who said: “This law is a world first – we now need to make sure it’s world-class.

“Addressing issues of aviation and marine shipping emissions is now the acid test of the Government’s aim to achieve a genuine reduction in CO2 emissions.”

Friends of the Earth’s Big Ask campaign for a tougher climate change law is also backed by Radiohead singer Thom Yorke, who said: “MPs have a chance to fix this when they vote on the law next week.

“We are on the verge of getting the world’s first climate change law. This is an amazing achievement, but there is one very large elephant in the room – it doesn’t cover pollution from ships or planes.”

A separate parliamentary motion calling for the inclusion of international aviation and shipping in the 80 per cent target has been signed by 74 Labour MPs – suggesting the number of rebels could rise further.

The Government’s position, backed by the Climate Change Committee it set up, is that it is near-impossible for countries to share out responsibility for the gases produced from international flights and shipping.

But the rebel amendment states that, if emissions from aviation and shipping continue to grow, the Government must compensate with extra CO2 cuts elsewhere.

Climate Change and Energy Secretary Ed Miliband has already bowed to pressure by increasing – from 50 per cent to 80 per cent – the Bill’s commitment for carbon emission cuts by 2050.

Mr Griffiths said he was “very encouraged” by discussions with Climate Change Minister Joan Ruddock, suggesting the Government might give way.

The rebellion looms only days after 16 Labour MPs – including John Cummings (Easington) and Denis Murphy (Wansbeck) – defied a three-line whip to try to defeat the Human Fertilisation and Embryology Bill.