Tasers use compressed air to fire two darts that trail electric cable back to the handset and release an electric charge (up to millions of volts) causing the victim to suffer temporary paralysis, which can lead to complications and death especially in physically vulnerable individuals. They are prohibited, and carry a five-year minimum prison sentence for their possession except in 'exceptional circumstances'. Taser guns look like pistols but are often disguised as other items e.g. mobile phones, lighters, torches.
Police use of Tasers (firing 50,000 volts) was approved in 2004 and has been increasing.