The Government today saw its majority cut to 23 as it survived an attempt by rebel Tory and Liberal Democrat MPs to force energy suppliers to slash their carbon emissions.
The rebel MPs joined forces with Labour to demand ministers set a target from 1 April next year for power companies to drastically cut their carbon output by 2030.
The Energy Bill had allowed ministers flexibility as it only said the Government may consider setting a target up until 2016.
But under a series of amendments tabled by Tory Tim Yeo, chairman of the Commons Energy and Climate Change Select Committee, and signed by 50 MPs including four Conservative and nine Lib Dem, the Government would have been compelled to set a target for energy companies by April 1 next year.
MPs only voted on one amendment to the Bill today - which would have forced the Government to set the target - but the rebels lost by 290 votes to 267, Government majority 23.
The remaining amendments tabled by Mr Yeo were not put to a vote.
Earlier, Mr Yeo said failing to force power companies to slash their carbon emissions will lead to higher prices for consumers.
He said: "The problem with this St Augustinian coyness, this promise of possible future chastity in the matter of greenhouse gas emissions but 'Please God, not just yet', is that by 2016 many investment decisions will have been made.
"If these lock Britain into a high greenhouse gas emission future, they will either prevent us from meeting our climate change commitments, or else will lead to the construction of fossil-fuelled generating capacity which has to be subsequently scrapped.
"And 2016 is also after the next general election. Delaying a decision until then creates another needless but harmful element of doubt about the Government's true intentions. I therefore urge MPs on all sides to support this amendment.
"Doing so will remove an element of uncertainty whose presence hampers investment, increases the risk of a capacity crisis and raises electricity prices unnecessarily. This amendment will not impose on the Government today any commitments it does not already claim to embrace."