The Parole Board could face more compensation claims as it grapples with a growing backlog of cases requiring oral hearings, public spending watchdog the National Audit Office (NAO) has warned.

The board has estimated that the number of oral hearings each year could increase from 4,500 to more than 14,000 after the Supreme Court ruled last year that prisoners are entitled to an oral hearing more frequently than before.

In its report on the Ministry of Justice for 2013/14, the NAO notes that the board received additional funding to meet this challenge and was undergoing significant change as it developed a new operating model.

The backlog of cases due to receive an oral hearing increased from 1,245 in September 2013 to 2,087 in March 2014.

‘The growing backlog of cases at the Parole Board will lead to further delays in releasing prisoners, making the Parole Board liable to more compensation claims and increasing the costs incurred by the prison system by extending the time prisoners are held,’ the NAO said.

‘It may also increase the number of prisoners held in crowded prisons.’

The 2013-14 National Offender Management Service annual report and accounts noted that 22.9% of prisoners were held in crowded prisons, where the occupancy exceeded the Certified Normal Accommodation in that unit.

The average annual direct cost per prisoner was £26,000 in 2012/13.