Supposedly the split has come about because the Tories were reluctant to agree to taxing car drivers even more heavily. Given that some three-quarters of the cost of petrol is already tax, it seems the Tories think that not losing the Jeremy Clarkson petrolhead vote should be as much a Tory priority as wooing muesli eaters. The other stumbling block was over green taxes rising as a share of GDP. That surely is not the objective of low tax, pro-growth parties like Cameron’s Conservatives and, errm, the new “regulate less, tax less“ Orange LibDems?

So what is really going on? Didn’t the LibDems realise that by embracing with the Tories on green issues the Tories had gained more eco-credibility and staked a claim to political turf previously the exclusive territory of the LibDems and the Greens? It only took Ming’s team a hundred days or so to work it out.

New politics might be about building issue based coalitions, but the brutal truth is that it is not worth it politically when it does fundamental damage to your brand’s USP. Too late now Guido suspects, Cameron has successfully established himself in the public eye as green*. Maybe Ming should get on his bike – if he can.

*The LibDems have paid the highest compliment to Cameron’s slogan makers by buying online Google advertising related to the phrase “Vote Blue, Go Green“. Why? Because that phrase hurts.