They will take part in a 12-month pilot scheme involving 10 forces allowing ordinary officers to carry the stun gun after training.

Only firearms officers have until now been able to use the high-voltage weapons but the Home Office has announced they will be able to use the stun gun in less serious incidents so long as they face violence or threats of violence.

From September non-firearms officers will also be able to use the weapon for the first time.

Amnesty International has opposed use of the US-manufactured weapons, claiming they can be lethal.

Police minister Tony McNulty said:"Police officers put themselves in harm's way every day and I want them to have the equipment they need to protect themselves and the public.

"Taser gives police an additional tactical option that is less lethal than conventional firearms and its use can help resolve incidents and limit the incidence of serious injury."

Apart from Northamptonshire, the trials will take place in Avon & Somerset, Devon & Cornwall, Gwent, Lincolnshire, Merseyside, Metropolitan, Northumbria, North Wales and West Yorkshire forces.