Probation officers across England and Wales will walk out at the end of the month in their fight against "reckless" coalition plans to privatise the service.

Union Napo announced yesterday after a special meeting in Birmingham that members would strike for 24 hours from midday on March 31.

General secretary Ian Lawrence said: "The coalition's plans to sell off the management of offenders to private providers so that they can make a profit from the justice system is a recklessly dangerous social experiment that presents massive risks to the safety of communities."

Napo has been fighting since last May against Justice Secretary Chris Grayling's universally condemned plans to sell off most of the probation service.

The government will carve up the profitable parts of all 35 probation trusts between private firms, while a new National Probation Service will be set up to handle 31,000 high-risk offenders each year.

The strike follows one in November and is only the fifth in Napo's 102-year history.

Shadow justice secretary Sadiq Khan also laid into Mr Grayling.

"Chris Grayling's relations with probation and prison staff, as well as barristers and solicitors, have plumbed depths unseen in living memory," said Mr Kahn.

"There's no evidence his reckless and half-baked plans to privatise probation will do anything to reduce re-offending and he should abandon them before he puts the public's safety at risk."

More than 1,000 probation officers are expected to appeal against jobs assigned to them as part of the sell-off.

The strike announcement came on the same day that the National Audit Office praised the probation service's performance.

And HM Inspectorate of Probation said there was "much good practice" among probation trusts.

Mr Graying plans to shut all 35 probation trusts on May 31.