Thousands of British prison officers staged a national strike over pay today, plunging the service into a fresh state of crisis.
The walk-out by warders across England and Wales took the government and Prison Service officials by surprise and led to picket lines being mounted outside jails across the country.
The action is illegal and could lead to the Prison Officers' Association being taken to court by the government later today
The union had its right to take industrial action taken away by the Conservative government in 1993 and even if it could strike, it would have to give seven days' notice before any action.
The union's executive decided yesterday to launch the 24-hour stoppage from 7.00am but officials warned that the strike could continue indefinitely until the dispute is resolved.
Union officials said they expected that prisoners would be kept locked up in jails while governors decide what action to take next.
The dispute has been brewing for months after POA members voted overwhelmingly in favour of strikes in protest at this year's pay award. An independent pay review body recommended a 2.5 per cent pay rise but the Government decided this should be made in two stages of 1.5 per cent in April and 1 per cent in October, which reduced the value of the award.
The POA said this was the last straw for prison officers already suffering low morale because of rocketing prison numbers and daily attacks staff in prisons.