Hundreds of prison officers are to be given Tasers for the first time in order to defend themselves against inmates, ministers announced last night.

The roll-out of the stun guns to 500 guards follows a trial involving 20 officers – and the Ministry of Justice may extend the scheme to include hundreds more.

The Tasers can generate 1,500 volts of electricity to incapacitate an attacker from a distance.

Some 10,000 prison officers will also receive stab-proof vests, a massive increase on the current 750.

The new initiative has been launched as officers face unprecedented levels of violence inside Britain's jails, which has seen guards being stabbed and even allegedly attacked with hot cooking oil.