Neither are scams but the UK is fond of permanently doing temporary things. Income tax in the UK was first imposed as a temporary measure to fund the Napoleonic Wars but after Waterloo it was never repealed since it brought in so much. Same sort of deal for the 70 mph national speed limit, it was a temporary measure in the 1960s apparently in response to someone caning it down the motorway in an AC Cobra and as we know, there’s nothing more permanent than a temporary solution.