As someone who doesn't drive, let alone drive a "Chelsea Tractor", this doesn't bother me much:
There's at least one Lib Dem councillor in Lewisham who'll be quite a bit poorer should his party be in a position to deliver on this tax pledge.
Oh, but no, perhaps not!
As the Guardian goes on to point out:
Also exempt would be existing purchases, so people who already own polluting cars would escape paying the tax.
Ah well, no one I've ever met has saod the Lib Dems are consistent.