In the election for London's Mayor, the Greens got just over three per cent of the vote. Leaving aside such misguided places as Norwich, where the Green Party gained three seats, they struggled elsewhere to poll anywhere near that.

In my native Calderdale, with its strong "Green" lobby, they managed only just over one per cent – less than the BNP, English Democrats and Independents, the other small groups that fought the election there.

Yet Labour, Conservatives, Liberal Democrats and Nationalists dance slavishly to the Green tune.

To hear him talk, the dear, departed Ken Livingstone was as Green as grass. Gordon Brown would carpet Britain, onshore and offshore, with wind "farms". David Cameron sails under the "Vote Blue, Go Green" banner. The Liberal Democrats are mostly eco-nuts. And the European Union goes berserk at the very mention of carbon dioxide.

Which brings me to the mystery. What ails them? Have they lost their powers of reason?

I ask because their pre-occupation with combating something that may or may not exist – that is, man-made global warming – is responsible for part of the growing burden of costs with which every household is now saddled. How much this energy/environmental burden contributed to Gordon Brown's Merrie May Day – otherwise known as Black Thursday – is far from clear, partly because consumers are unaware of what they are paying.

If they knew, all our politicians would belatedly bring some cost/benefit analysis to their environmentalism. It has been distressingly absent so far. Would the Prime Minister have had solar panels and Cameron a wind turbine installed on their houses had they known they would never get their money back on the "investment"?

There are good and bad "buys", but they don't come much worse than waiting for decades, even half a century, for any return on your capital. It doesn't say much for their business acumen.

Belatedly, Labour MPs are pressing Gordon Brown to ditch some of his so-called green taxes since their environmentalism is only as strong as the economy or their political skins. So, how much is the Government forcing us to shell out to try to make them appear greenly virtuous?

There's the rub. Governments are not in the habit of dishing
out research grants to academics to show how stupidly they use our money, so all I can offer you are pointers.

Let's forget the so-called climate change levy (CCL), which has as marginal an effect on domestic consumers' bills as it does on CO2 reduction. Instead, the real damage is done by Renewable Obligation Certificates (ROCs) designed to encourage the development of wind, wave, tidal, solar and other "renewable" forms of electricity. These are as idiotically conceived as the CCL, since nuclear and large-scale hydro-electricity, which emit next to no greenhouse gases, are excluded from both.

ROCs latterly have provided a 100 per cent subsidy substantially to wind power – so far the only major renewable source of electricity – and earlier this year, the Business Department forecast they would cost £23bn by 2020, or, nearly £1,000 per household. And for that we would optimistically get only 14 per cent of our electricity – and then only when the wind was blowing.

Unfortunately, that figure was out of date when it was calculated because Tony Blair had signed up to a battily impractical EU requirement to produce 20 per cent of our energy – and not just electricity – by 2020 from renewables.

If we are to offset the massive use of oil and gas for transport and domestic heating with renewables, we shall, as things stand, have to generate up to 45 per cent of our power with wind. So that will treble the eventual cost to £3,000 per household – without providing a reliable power supply.

Ofgem, the energy regulator, says that eight per cent – or £80 – of the current average current gas and electricity bill can be attributed to environmental charges and this is only going to rise with the billions required to link remote and largely useless wind farms to the grid.

This is not to mention more generally the costs of the carbon trading and offsetting rackets, the Treasury's punitive tax revenue from petrol and
diesel, Gordon Brown's new "green levy" doubling car tax revenue to £4bn while, on the Treasury's own admission, reducing carbon emissions by less than one per cent, and taxes on rubbish.

Why do we put up with this "green" extortion to so little purpose? That's the real mystery.