If vehicles are parked illegally on roads, they'll be clamped. The wheel can only be clamped by an 'approved' device that is placed by the police or other authorised persons. A notice will be fixed to the vehicle stating how it can be released. There will be a fee to release the clamp. It's an offence to interfere with a clamping device.
Clamping, towing and immobilising of vehicles parked on private land are illegal in England and Wales.
In Northern Ireland, only unlicensed vehicles can be clamped. There will be a consultation in Northern Ireland to determine whether the ban in England and Wales will be extended to Northern Ireland.
In Scotland, clamping on private land is unlawful because it is seen as extortion.