The UK's newest government department has announced a reorganisation less than a year after it was launched.
Prison overcrowding remains a problem in England and Wales
Justice Secretary Jack Straw says the Prison Service is being merged with other parts of the justice system.
The move comes after widespread criticism of the National Offender Management Service (Noms) partly set up to tackle rates of reoffending.
The Tories attacked the reorganisation, saying the government's strategy to cut reoffending is now in tatters.
Ministers set up Noms to join up the different parts of the criminal justice system dealing with offenders.
The Home Office believed it could cut reoffending if it could manage more closely the rehabilitation of offenders between custody and the community.
However, the umbrella body over prisons, probation and other elements of criminal justice was accused of wasting money.
Its flagship computer system to provide "end-to-end" tracking of offenders and their progress towards rehabilitation has been massively scaled back.
Review of operations
Announcing the changes to the Ministry of Justice, Mr Straw said the reorganisation was part of the department's review of operations, including the future of prisons.
The Prison Service and Probation Service would be brought together in a "streamlined headquarters" from 1 April, said Mr Straw.
"The new structure will provide the Ministry of Justice with a sharper focus on its key priorities, including public protection and reducing re-offending, and improving relations with the judiciary, while streamlining leadership across the whole of the Department's agenda.
"These changes will ensure a more joined-up approach to issues of justice and constitutional reform and will ensure that we create the right conditions for the delivery of the Ministry of Justice's wide agenda."
But shadow justice secretary Nick Herbert attacked the announcement, saying it was "farcical" to announce a re-organisation less than a year after the launch of the Ministry of Justice.
"This announcement effectively spells the demise of Noms, which has only been in existence for three years, yet has cost the taxpayer over £1bn at a time when frontline criminal justice services and the prison budget are being cut," he said.
"The scaling back of the IT system has already fatally undermined the principle of offender management which, as this announcement confirms, is only being applied to some offenders."
Harry Fletcher of union Napo, which represents probation officers, said the announcement was a "tacit admission" that Noms had failed.
"There is however a real risk that probation will be diminished in the new structure because of the financial demands of the prison service," said Mr Fletcher.
"Ministers must ensure that the changes do not result in yet another over bearing bureaucracy and that resources are diverted to the grossly under funded front line."