Police stun gun may not be sufficiently powerful

The effectiveness of electronic stun guns – expected to be issued to police officers before the end of the year – has been called into question in a Home Office report that suggests that some criminals can shrug off the power blast and continue their assault.

The Metropolitan Police and Northamptonshire Police are planning to arm a small number of officers with Taser stun guns, capable of paralysing offenders with 50,000-volt electric shocks. The fresh evidence emerged as Kent Police said it was in line to become the first force in Britain to use plastic baton rounds. Firearms officers are to be trained to fire rounds that have only previously been used in Northern Ireland.

As reported in The Independent, the Metropolitan Police intends to train and equip firearms and riot officers with the stun guns, which can be fired from a distance of up to 21 feet (6.5m).

The introduction of the weapons is a response to a rising number of incidents in which police officers have been confronted by men armed with swords and knives.

But an interim report by the Police Scientific Development Branch (PSDB), which has been asked to fast-track tests on the Taser, says: "There have been a number of cases where individuals have not been fully incapacitated by the device. Their muscles have contracted while the Taser is active, but they have not fallen to the ground and, as soon as the power is turned off, they have been able to remove the barbs from themselves and continue their attack."

The report also notes the weapon's effectiveness can be seriously affected by low battery power and cold temperatures.

The PSDB says that, in the United States and Canada, where Tasers are widely used, a number of failures have been blamed on officers conducting "spark tests" to ensure the devices are working correctly before going on duty. This led, in some cases, to draining of the batteries and the guns having less of a stunning effect. The hand-held gun, which fires barbs attached to a power pack by thin wires, was also found to break easily when dropped.

The report does, however, praise the more powerful 26-watt Taser M26 models, which it says are close to 100 per cent effective "regardless of the pain tolerance or mental focus of the individual". Scotland Yard is believed to be examining the M26. The device proved accurate and, during testing on a static target up to ranges of 21 feet, a barb missed on just one occasion in more than 30 shots.

Civil rights' groups, such as Amnesty International, have expressed concern about the use of Tasers.

A spokesman for the Association of Chief Police Officers said: "It's still going to be several months before it is going to be available to the police, assuming it is considered safe and effective. The urgency with which these issues are being considered has increased."

The importance of finding a non-lethal alternative to guns was highlighted in July by the case of Andrew Kernan, who was shot dead by police in Liverpool as he brandished a samurai sword. The 37-year-old, who suffered from mental illness, was killed after ignoring calls to drop the sword.