Amber Rudd, Secretary of State at DECC, was all over the media yesterday, making out that the UK had played a big part in securing the historic agreement in Paris*. Unfortunately, nothing could be further from the truth.

The transparent duplicity of the UK’s position had been rumbled the week before, when David Cameron did one of his grandiloquent numbers exhorting all and sundry ‘to follow the UK’s lead’. By then, courtesy of the UK’s assiduous NGOs, almost everyone at COP21 had heard the true story about his Government’s single-minded demolition of pretty much everything that once gave the UK its ‘licence to lead’. ‘Shameless hypocrisy’ was just about the politest notice that Cameron got in Paris.

But all that matters now is what happens next. Cameron decided immediately after the May Election to delegate the whole climate agenda to George Osborne, and George Osborne wasted little time laying waste the (admittedly somewhat muddled) policy terrain that lay before him. I don’t need to repeat either the extent or the seriousness of the string of decisions taken over the last six months – just check out earlier blogs.

By all accounts, Cameron only woke up to the impact of all of this a couple of months ago. He then made a half-hearted attempt to influence Amber Rudd’s so-called ‘energy re-set’ (putting all our eggs in the nuclear and fracking baskets!), only to get distracted all over again by Syria and the EU. Which means, right now, whatever else the Cameron legacy may eventually lay claim to, his personal claim to playing any part at all in probably the most critical shift in the modern history of humankind (transitioning from fossil fuels to renewables, storage and efficiency) will be null and entirely void.

Unless, of course, he decides to get back in the low carbon groove, to recall what it felt like to be out there hugging huskies and installing rooftop wind turbines, and put an end, once and for all, to the malicious and massively damaging influence of Osborne, Lawson and Paterson.

For Osborne has not done all this on his own. Nigel Lawson’s unremitting efforts to weaken the consensus on climate science has undoubtedly been very persuasive for dozens of Tory backbenchers. But now that his so-called ‘think tank’, the Global Warming Policy Foundation, is under scrutiny from the Charity Commission, maybe we’ll be hearing less of Lawson. Somehow, I rather doubt it. People in his position have no shame in peddling manifest untruths and junk science.

And as for Owen Paterson (the short-lived Secretary of State at Defra between 2012 and 2014), he finally revealed his true denialist colours via the pages of the Daily Telegraph (where else?!) on Saturday, calling for the Climate Change Act to be repealed – as ‘Ed Miliband’s most pernicious legacy’.

The Climate Change Act is of course the one thing that Conservatives might still feel some residual pride in having helped to bring about whilst in opposition in 2008. And it was of course the one thing that David Cameron was only too happy to brag about in his Paris speech – for lack of any single new achievement since his re-election earlier this year.

Does he care? Who knows. Probably not. But politicians who know they’re coming to the end of their time in office are invariably to be found seriously obsessing about their ‘legacy’. He must now see, post-Paris, that being stuck in the laggards’ brigade, rather than up there amongst the leaders, is embarrassing at best, and possibly just a bit humiliating at worst.

And there’s still plenty of time for him to get himself on the right side of this historical divide, and put Osborne, Paterson and Lawson back in their boxes to ensure that the UK economy prospers in this brave, new low-carbon world now emerging in front of our eyes.

*And it is an historic agreement. NGOs (and isn’t it great to see Friends of the Earth out there on the front foot again?!) are right to point out that it still doesn’t go far enough, but it goes so much further than most people thought possible even a few weeks ago. And it will greatly help shame the backsliders (like India, Russia and the UK) into action.