Ken Livingstone, London’s mayor, last week caused consternation among the Chelsea tractor set by appearing to threaten a punitive rate of congestion charge, £25 instead of the current £8. Cue cheers from the tree-hugging community and an equally passionate response from the 4x4 lobby. One columnist – and there are no prizes for guessing which newspaper she writes for – complained in all seriousness that she needed her 4x4 to attend shooting and fishing events at weekends, and if Red Ken had his way then she would have to leave London altogether.

That alone makes me want to tax the shirts off 4x4 drivers. I hate the things – I am a cyclist, I have a young child with a head at bull-bar height and I am as worried as anyone else about the planet. These are needlessly wasteful vehicles and there is a growing body of evidence that they make drivers feel so safe as to encourage more reckless driving. But Mr Livingstone’s proposal is idiotic.