I'm actually a big fan of those hoverboard thingys (I think they're called Swegways), because when you see someone riding one you instantly know they're not a person you should be pals with. They really make socialising easy! Sadly, these tosser-tags will soon be no more, because the Old Bill has only gone and made them illegal. According to the CPS:
1."I have a self-balancing scooter and I want to ride in on the public road, is it legal for road use?"
No. Vehicles must be approved via ECWVTA or MSVA in order to be licensed and registered. Self-balancing scooters would not currently meet the requirements of these schemes so are not legal for road use.
2."I have been riding a self-balancing scooter on the public footway (pavement) outside my house, have I committed an offence?"
Yes. It is an offence under section 72 of the Highway Act 1835 to ride or drive a vehicle on the pavement. It is only an offence under this Act in England and Wales. In Scotland it is an offence under section 129(5) of the Roads (Scotland) Act 1984.
3."Where can I ride a self-balancing scooter?"
You can only ride an unregistered self-balancing scooter on land which is private property and with the landowner's permission. The Department for Transport would advise that appropriate safety clothing should be worn at all times.
4."I have seen people using electric bicycles on the road without registration. Why are they permitted but a self-balancing scooter is not?"
Bicycles are covered by different rules to those applying to self balancing scooters. Electrically Assisted Pedal Cycles must meet the requirements of the Electrically Assisted Pedal Cycles Regulations 1983. Electrically Assisted Pedal Cycles that conform to these regulations are considered to be pedal cycles and as such are allowed to use cycle facilities such as cycle lanes on the road and cycle tracks away from the road which other powered vehicles are prohibited from using. A self-balancing scooter does not meet these requirements as it cannot be pedaled.
Here's a picture of Lily Allen riding one while smoking a cigarette, just in case you need further convincing of their awfulness: