The British government’s devious, cynical, hypocritical energy policy has just unravelled horribly – with the leak to The Ecologist of a private ministerial letter which admits that Britain hasn’t a hope of meeting its legally-mandated “clean energy” targets.

Officially, Britain’s line is that David Cameron’s self-styled “greenest government ever” is well on course to deliver on the promise Energy Secretary Amber Rudd made in June this year when she told parliament:

“The renewable electricity programme aims to deliver at least 30% of the UK’s electricity demand from renewables by 2020. We are on course to achieve this objective. Renewables already make up almost 20% of our electricity generation and there is a strong pipeline to deliver the rest.”

Unofficially, this is but a pipe dream. Rudd admits this in the leaked letter, which was supposed only to have been seen by senior ministers and civil servants.

“The trajectory then increases substantially, and currently leads to a shortfall against the target in 2020 of around 50 TWh (with a range of 32 – 67TWh) or 3.5% points (with a range of 2.1 – 4.5% points) in our internal central forecasts (which are not public). Publically we are clear that the UK continues to make progress to meet the target.”

What this means is that Britain is going to fall about 25 per cent short of its renewable energy targets by 2020.

None of this would remotely matter, of course, if these targets were just notional aspirations. Unfortunately they are legally binding thanks to the 2008 Climate Change Act which only five MPs voted against and which everyone else voted for – including most of the Cabinet and the Prime Minister David Cameron. So Britain – unlike any other country in Europe – actually has to meet these targets or face judicial review, not to mention enormous fines imposed by the European Court of Justice.

All of this was entirely foreseeable.

As critics like Christopher Booker have been arguing since it was signed, the Climate Change Act was the most mindlessly expensive and pointless legislation in British parliamentary history. Originally estimated to cost the taxpayer £18 billion a year every year till 2050 (a total of £734 billion), it is now more realistically reckoned (by the International Energy Agency and the EU itself) that it will cost closer to £1.5 trillion.

Much of the blame for this lies with disastrous former Labour leader Ed Miliband who, in a fit of zeal in his role as Britain’s first Energy and Climate Change secretary, decided to make the energy targets even more stringent and hopelessly unattainable than had originally be proposed. Another culprit is Bryony Worthington – now speaking up for eco-lunacy in the House of Lords as Baroness Worthington – a climate activist from the hard-left environmental group Friends of the Earth who, bizarrely, was given carte blanche by the government to write Britain’s renewable energy policy.

But still the disaster might yet have been averted – or at least the damage mitigated – had the then leader of the opposition, David Cameron, chose to subject the proposed bill to closer scrutiny. Cameron didn’t because he has never been much interested in detail and because he was on a mission to “detoxify” the Conservative brand by trying to outflank the left on environmental issues. (“Vote blue, go green”, as the slogan had it).

The situation only worsened in the Coalition years when Cameron decided to hand the keys to the Department of Energy and Climate Change to his rabidly green, economically illiterate Coalition partners the Liberal Democrats.

What this meant was that all the very worst environmental ideas inherited from the Labour era under Tony Blair and Gordon Brown were now entrenched under administration were the Prime Minister was supposed to be Conservative.

Though Cameron has long since lost patience with the environmental lobby (“cut the green crap” as he put it to one of his ministers), he has been forced publicly to pretend otherwise a) so as not to rock the boat with his EU partners b) because he hates confrontation c) because it suits his party’s centrist image to wrap itself in faux-greenery and d) because there’s nothing he can do to stop it without hours of parliamentary argy bargy because thanks to the Climate Change Act its green policies are embedded in law.

Up till now, his solution has been a characteristic fudge. Appoint a minister – Amber Rudd – who makes all the right green noises but who is yet prepared mercilessly to slash all Britain’s unaffordable green measures: cutting subsidies for solar “farms”; halting the growth of onshore wind “farms”; removing tax relief for investors in “community” renewable energy projects; etc.

Unfortunately the greenies have now noticed – and found a smoking gun – as inevitably they were always going to.

Thanks to this leak to The Ecologist – no doubt by one of the green ideologues who infest the Civil Service – Rudd can expect an extremely rough ride this morning from parliament’s Energy and Climate Change Committee. Most of its members are fully-paid-up believers in man-made climate change.