Scotland Yard's plan to arm officers with electric stun guns was backed yesterday by the independent authority that investigates deaths in custody and police shootings.
The Police Complaints Authority (PCA) said that it supported a trial of the "Taser" stun guns, which are capable of paralysing offenders with their 50,000-volt electric shocks, but stressed that their use should be strictly limited.
As reported in yesterday's Independent, the Metropolitan Police intends to train and equip firearms and riot officers with the guns. Northampton Police is also expected to test the guns, which can be fired from a distance of up to 21ft.
The introduction of the weapons, classified as "less than lethal", is a response to a growing number of incidents in which police officers have been confronted by men armed with swords and knives. The Met, which hopes to have the US-style weapons in use by Christmas, wants a device that is not as lethal as a firearm but more effective than CS gas spray.
Ian Bynoe, the deputy chairman of the PCA, said: "The need to find an alternative to firearms is imperative and, in principle, we would support the decision to try out Taser stun guns."
Mr Bynoe added: "We would see stun guns being used when people are clearly armed with a knife or a sword. But we have reservations about any proposals to issue them to officers involved in public order situations."
The issue of how to tackle armed offenders has been highlighted by the case of Andrew Kernan, a schizophrenic who was shot dead by Merseyside police last month after brandishing a samurai sword in a street in Liverpool.
There are thought to be health risks connected with the use of the Taser gun – which fires two darts that trail electric cable back to a powerful charge pack – particularly for people with heart complaints. The barbed darts hit their target to trigger an electric burst which is sent along the cable, causing the victim's muscles to contract violently.
Susan Kobrin, spokeswoman for Amnesty International, said: "We understand that police officers need to protect themselves, but our concern is that there could be significant risks attached to the use of stun guns. We need to see a thorough independent investigation before they decide to deploy them. Any officer that uses these devices must be properly trained and there should be vigorous guidelines and monitoring."
Amnesty has studied the use of the Taser and other stun guns in the US and has concluded that some prison officers use them as torture weapons. The group also said that Rodney King, the black man whose assault by police sparked riots in Los Angeles in March 1991, was shocked twice with a stun gun before being beaten by three officers.