Self-balancing scooters are illegal to ride in public in Britain, according to the Crown Prosecution Service.
The boards - also called hoverboards or space boards - are too unsafe to ride on the road, but too dangerous to ride on the pavement, according to legislation.
They are therefore only legal to use on private property and only with the landowner’s permission, the CPS says.
The CPS originally issued the guidance for Segway scooters but the popularity of the newer boards has prompted the police to tweet a warning.
Simon Benson of hoverboard distributor Ghetto Gadgets told the Guardian: “If the authorities give any impression that the use of hoverboards in some circumstances is unlawful, then I expect sales to soar."
Clearly customers need to take advice, but millennials are not going to take kindly to the authorities using a law that pre-dates the penny-farthing to tell them what they can or can’t do on the streets of Britain.