Christopher Booker's piece about Margaret Thatcher in the Telegraph concentrates on the fact that in her memoirs she repented of her pioneering emphasis on man-made global warming (AGW). Booker's aim is to strip away Cameron's attempt to wrap his (and his coalition partner's) adamantly warmist policies in the Thatcher's political mantle.
Booker fails for the simple reason that the truth or otherwise of global warming was not Thatcher's - and is not Cameron's - principal reason for espousing AGW. Thatcher pushed for the formation of the UN's IPCC and funded the Met Office's Hadley Centre and the University of East Anglia's Climate Research Unit (CRU) because she needed to offset the political fall-out from the 1986 Chernobyl disaster if she was to begin the construction of a new generation of nuclear power stations in Britain.
When asked how the 'Climategate' revelations about malfeasance at CRU had affected his view on global warming before the election, Cameron's office replied that it 'was an established basis for public policy', hence not subject to modification. That was an entirely Thatcherite reply: his hopes for pursuing an independent and secure energy policy are invested in AGW, therefore he will continue to profess belief in it, regardless of evidence to the contrary.
That's the problem with what I call political instrumentality, which is proclaiming one objective with the secret aim of achieving another. Unlike billiards or snooker, a cannon in politics does not follow the laws of physics, and the third ball can and usually does take off along an unpredictable line.
Politicians simply are not skilled enough, nor are human reactions remotely logical enough, to attempt it: but they keep on doing it, because they think that having conned their way into power on the two-dimensional electoral chess-board, they are clever enough to do the same in the three-dimensional world.
P.S. Another example of instrumentality was the decision by the World War II government in the USA to permit companies to pay for health insurance for their employees in lieu of frozen wages. The untaxed extra came to distort the free movement of labour as well as constituting a punitive tax on the self-employed. The employees of US companies are only now waking up to the fact that Obama's health care bill has made their medical benefits taxable for the first time in 70 years. As a self-employed person who was mugged by the monstrous US health insurance companies when I lived there, I cannot help but smile. Welcome to the real world, guys.