George Osborne’s father-in-law has fuelled the civil war within the Coalition Government - and between rival wings of the Conservative Party - over energy policy by claiming that the Chancellor is privately manoeuvring to undermine David Cameron’s climate change promises.

Secret filming shows Lord Howell, who also advises the Government on energy, and Peter Lilley, a senior Tory MP who is a climate change sceptic, claiming Mr Osborne shares their hostility to building more onshore wind-turbines.

“The Prime Minister is not familiar with these issues, doesn’t understand them… Osborne is of course getting this message and is putting pressure on,” Mr Osborne’s father-in-law Lord Howell told a a Greenpeace activist posing as an anti-wind farm lobbyist, who was covertly recording him.

The Energy and Climate Change Secretary, Ed Davey, a Liberal Democrat, is already in open conflict with one of his Tory deputies, John Hayes, over the issue, and more than 100 Tory MPs have publicly opposed the construction of more wind-farms.

British targets to cut the CO2 emissions scientists believe are causing global warming are “absurd”, he said.

Mr Lilley, who has just been appointed to the climate change select committee, struck a similar note, saying he believed the Chancellor “privately regrets all the [green] commitments that have been made”.

He claimed that Mr Osborne used the recent ministerial reshuffle to “get people into key positions who could begin to get the Government off the hook from the commitments it made very foolishly”.

He cited the example of Mr Hayes, but Tory opponents of energy policy were also cheered by the appointment of Owen Paterson two months ago as the Environment Secretary.

Mr Lilley claimed Mr Hayes was “prepared to duff up” Mr Davey on the issue of wind-farms and, in an unreleased piece of footage, ridiculed Greg Barker, a Tory energy minister, as “barking”, a “complete nutter” and “away with the fairies”.

Tonight Mr Osborne issued a statement insisting: “The Chancellor supports Government policy which has helped secure record investment into the UK energy infrastructure.”

Senior Liberal Democrat sources acknowledged the issue was causing tensions at the highest levels of Government and deterring investors in renewable energy. One source said: “I’m afraid the problem is coming from the Treasury. But it makes the Liberal Democrats in government more determined to deliver on the Coalition Agreement and ensure we secure investment in green energy and renewables.”

The tensions were underlined on Tuesday night when Mr Hayes claimed that once the wind-farms currently planned were built it would be “the end of the story” – a stance that put him directly at odds with Mr Davey who immediately slapped down his Tory deputy.

The Conservative MP Chris Heaton-Harris apologised for appearing to encourage a potential rival candidate – and opponent of wind-farms - in today’s Corby by-election.

He was secretly recorded by Greenpeace saying he “suggested” James Delingpole put himself forward as an independent to push the issue up the agenda and “cause some hassle” during the campaign.

Mr Heaton-Harris also said: “At the moment, it is still looking a lot better with Owen Paterson and John Hayes. I’ve still got Ed Davey to dump on from a height somewhere.”

Lord Howell, whose daughter Frances is married to the Chancellor, also risked stoking up diplomatic tensions with the Gulf state of Qatar by saying there was a strategic case for buying its gas as an alternative to renewables.

He said: “Qatar is a great place and it’s full of skyscrapers and rich people. But it’s also rather near to a lot of jihadists... If Qatar was just to - it’s about the size of Guildford - go into chaos, we would be up shit creek we really would.”

Tonight Mr Lilley said: “My remarks about George Osborne were taken from reading the newspapers. I don’t have any inside knowledge about what is going on in his head.”

He accepted he had not chosen his words about his fellow Tory Greg Barker very delicately, but added: “I don’t rate his political judgement very highly.”