Dartmoor has been described as 'the prison that time forgot'

HMP Liverpool and HMP Dartmoor are the latest prisons selected by the government to be "performance tested".

Prisons minister Hilary Benn claims the scheme drove standards up in Reading and Leicester prisons, and said two more prisons will also be subjected to performance testing in June.

"Performance testing will ensure that prisons really are working towards delivering improvements which will mean better treatment of prisoners and more opportunity to reduce offending," he said.

At the same time, prisons chief Phil Wheatley announced a new league table for all 129 public sector jails in England and Wales.

Each jail will be awarded points between one and four - where one is "failing" and four is "exceptionally high performing".

The tables will be published quarterly on the Prison Service website, but private jails will be excluded and will face a separate system set up by the Home Office's Commissioner for Correctional Services, Martin Narey.

High performing jails will get "increased certainty over future funding levels" and extra cash which the governor can use to reward staff or to invest in the jail.

'Opportunity to improve'

Mr Benn said: "Liverpool and Dartmoor should see this as a positive opportunity to improve performance and I hope that they will grasp this challenge."

Last January the Chief Inspector of Prisons said inmates at HMP Dartmoor were routinely abused and degraded by officers desperate to cling to the jail's "hard" image.

The 700-inmate jail - one of the best-known in Britain with its bleak moorland location - was described as "the prison that time forgot" by Anne Owers.

HMP Liverpool is the largest jail in western Europe with 1,500 inmates.

A Prison Service spokesman said it was failing to improve in many areas such as resettlement, time out of cells and purposeful activity for prisoners.

Mr Wheatley said of the new performance league tables: "This programme will make the process of measuring performance in the Prison Service more transparent with the emphasis on pulling up the poorest performers to the standard of our best prisons."