text: It follows last month's announcement that Birmingham Prison is to become the first jail in the UK to be privatised.
  Prison officers are banned from going on strike, but the ballot will seek the members' views about "industrial action up to and including strike action".
  The government says contingency plans involve the police and military.
  About 30,000 members of the Prison Officers' Association (POA) in England and Wales will take part in an indicative ballot, which will be considered by union leaders before they decide their next move.
  POA general secretary Steve Gillan said prison officers were "angry" at the government's privatisation plans.
  National chairman Colin Moses said: "It is vital members have their say through the ballot box and decide what course of action they are prepared to take to support their colleagues, who have been sold off to the private sector."
  "Prisons should not be run for profit and whilst Ken Clarke took great pride in announcing the privatisation of these prisons, the POA remains of the view that it is the state's responsibility to imprison its citizens and not profiteers".
  A Ministry of Justice spokesman said its aim was to avoid "any form of industrial action" and it would continue to talk to unions.
  "However, given the risks and complexities involved in running prisons, it is sensible and appropriate to review our contingency plans for dealing with widespread industrial action," he said.
  "There was a previous trilateral agreement with the police and the military for the provision of support to prisons and we are currently reviewing those arrangements and working with the MoD and police to ensure that our contingency arrangements are as strong as possible."
  Source: Prison Reform Trust
  In March, security firm G4S was awarded the contract to run Birmingham's 1,400-inmate jail and Featherstone 2 prison, a new jail opening near Wolverhampton.
  At the time, Justice Secretary Ken Clarke said the move would save money and improve performance on issues such as cutting reoffending rates.
  Birmingham and Featherstone 2 were among four prisons whose management had been put out to tender.
  Mr Clarke also announced Serco would continue to run Doncaster Prison, which was built by a private company, and it would become the first prison to be run on a "payment by results" basis, with the firm getting its full payment only if reoffending rates were reduced.
  The other prison - Buckley Hall, in Rochdale - will continue to be run by HM Prison Service.
  Thirteen private prisons already exist in the UK - 11 in England in Wales, and two in Scotland - but Birmingham is the first existing public sector prison to be contracted out.
  The 13 prisons are each managed by one of three firms - Kalyx (previously UKDS), Serco or G4S Justice Services.
target: Prison officers in England and Wales are to be balloted on industrial action over the privatisation of jails, the Prison Officers' Association has said.