Before the election, the then shadow chancellor George Osborne used to give speeches about how Labour had given green taxes – fundamentally a good thing – a bad name.

Now, in the heat and rush of the comprehensive spending review, that is exactly what he has done with his last-minute raid on the CRC Energy Efficiency Scheme (see our coverage).

This was by far the most striking and concrete environment/carbon element of last week’s Comprehensive Spending Review, which left low carbon business largely in the dark. The green investment bank, the renewable heat incentive, investment in carbon capture and storage are all still to play for.

But as for the CRC, now we know. Instead of being recycled back to CRC participants in line with energy saving merit, all the money raised by allowance sales will now go to the Treasury – and not necessarily be spent on cutting carbon.

The last-minute change grabs an extra £1bn a year for the exchequer, transforming a complex, revenue-neutral incentive scheme into a complex new carbon tax. No one saw it coming.

At a time of growing moans from business and think tanks about the plethora of overlapping financial instruments targeting energy and emissions, the changed CRC scheme is now just one more. It muddies the water for the forthcoming reform of energy markets and the climate change levy.

Industry and commerce’s anger at the lack of consultation and the imposition of a new tax in difficult economic times is justified and understandable. And the Osborne raid is even harsher for a public sector facing drastic spending cuts.

The one positive is that the rejigged CRC should cut more carbon.

Because however cross bosses might be, the business case for saving energy is now much stronger for CRC participants. And provided the government sticks with its plan for a CRC league table based on participants’ energy saving performance, the reputational driver remains just as strong.

There had been some fretting about whether the CRC scheme gave participants a perverse incentive to delay energy saving investments in order to improve their position in the league table, boosting their reputation and gaining more cashback from the recycling of allowance payments.

The counter-argument was that there was far more money to be  gained by getting on with saving energy now. And now that argument has just got much, much stronger.

Now DECC needs to get on with issuing what will hopefully be its final, final  consultation on the troubled and changeable CRC scheme.