Image caption The plans could see low and medium-risk offenders monitored by private firms and charities

Probation officers in England and Wales have voted to strike over government privatisation plans.

Private firms and charities are currently bidding for contracts worth £450m to supervise 225,000 low and medium-risk offenders each year.

The probation officers' union, Napo, said there had been a 46% turn-out, with more than 80% voting yes for action. No date has been given.

It warned selling off the Probation Service would boost re-offending rates.

The government called the vote "disappointing" and said it would continue to engage with unions.

Under the proposals, most of the Probation Service's work will be done under new payment-by-results contracts, to be awarded in 20 English regions. The whole of Wales will be one region.

The contracts would mean that low and medium-risk offenders will be supervised by a mix of private firms, charities and voluntary groups.

More than 700 organisations from around the world, as well as hundreds of British firms, have expressed interest in the contracts, the Ministry of Justice has said.

'Open to talks'

We are committed to introducing our important reforms, which were widely consulted on Jeremy Wright, Justice Minister

A new public sector body, the National Probation Service, will be created to deal with the rehabilitation of 31,000 high-risk offenders each year.

Napo general secretary Ian Lawrence said his organisation would pursue the mandate for industrial action "with vigour" but would also seek "to avoid this if possible by way of further negotiations with ministers".

He said "decimating the award-winning public sector Probation Service and selling it off to the likes of G4S and Serco will result in increased re-offending rates, a lack of continuity in risk management, and will see the privateers making huge profits at the expense of victims, offenders and taxpayers."

Justice Minister Jeremy Wright said news of the strike was "disappointing" but stressed there were "well-established contingency arrangements".

"More than 600,000 offences were committed last year by those who had broken the law before, despite spending £4bn a year on prisons and probation," he said.

"The public deserves better and we are committed to introducing our important reforms, which were widely consulted on.

"We will continue to support staff and engage with unions as our reforms move forwards."

'Huge opportunities'

Max Chambers, head of crime and justice at the right-leaning think-tank Policy Exchange, said industrial action was not the way forward and called for the Probation Service to "get on board" with the changes.

"It's no surprise that some probation staff are worried about the future, but striking is not a very clever move and could put the public at risk," he said.

"There are huge opportunities that payment-by-results can offer staff, including greater professional discretion, more freedom to innovate and the chance to have a stake in their own mutual organisations."

A government-wide review of all contracts held by G4S and Serco is being conducted after it emerged the firms had overcharged the government by "tens of millions" for electronic tags for criminals.

Serco has said it is "co-operating fully".

G4S has said it "co-operated fully" with a previous audit started earlier this year and was conducting its own inquiry but was not aware of any indications of dishonesty or misconduct.

The two firms will not be awarded any contracts until the government audit is completed, but Justice Secretary Chris Grayling has allowed them to bid for the probation service.