Even though hoverboards have only popped up recently, they’re illegal in the UK thanks to a 180-year old law. The 1835 Highways Act states that people cannot use the footway to “lead or drive any horse, ass, sheep, mule, swine, or cattle or carriage of any description” which, sadly, includes hoverboards. I think they come under the heading of ‘carriage’, as they’re very unlikely to be considered to be livestock, except for VAT purposes.