It appears that Boris at very long last is going to ‘review’ the current rules that exempt hybrid vehicles from the London congestion charge. And, being a bright boy, when he does he will realise the tax shows as little understanding of what it was trying to achieve as his predecessor, Mr Livingstone, who’s work it is.

Right now you can swan around the capital in a Lexus LS600h without it costing a bean despite it pumping out 219g/km of CO2. But try the same in any one of the hundreds of conventionally powered cars emitting less than half this amount of CO2 and charged you will be.

The next generation of Polo BlueMotion will not only manage over 80mpg on the combined cycle but also emissions of just 87g/km, both numbers better than those of even the very latest and most saintly Toyota Prius. Can there really be an argument for its inclusion and the exemption of 200g plus hybrids? Clearly not, unless of course the charge was just another way of extorting cash from the poor old motorist hiding behind a veil of token environmentalism.

The problem for Boris, even if he does see the light and makes this ludicrously unfair tax CO2 based, is where it kicks in. When the charge was first proposed, Livingstone said he’d consider letting in any cars emitting under 120g/km free, a hurdle you could now duck under in a 3-series BMW, which I’m fairly confident is not that he was thinking about at all. And if we think CO2 emissions are low now compared to what they were then, that’s nothing compared to where they’re going to be in a few years time.