Overcrowding in the region's prisons - with multiple prisoners often crammed into cells meant for one - is being blamed for a stark rise in assaults on inmates and staff.

Eastern Daily Press: A Wing at Norwich prison. Photo: Angela SharpeA Wing at Norwich prison. Photo: Angela Sharpe (Image: Archant © 2009)

Ministry of Justice figures show that HMP Norwich, Wayland and Bure are all oversubscribed. HMP Norwich has 717 prisoners in just 616 spaces. HMP Wayland has 929 prisoners living in 865 spaces and HMP Bure 652 prisoners in 604 spaces

Campaigners say that the unchecked rise of the prison population is responsible for the huge increase in assaults on staff and other inmates - a situation described last week as a 'national emergency'.

The Prison Service measures its own capacity in terms of Certified Normal Accommodation - the number of prisoners it says it can accommodate in a 'good, decent standard of accommodation'.

However, with the majority of prisons overcrowded across England and Wales, they have a separate measure called Operational Capacity. It is the maximum number of prisoners the Prison Service says each institution can safely handle while maintaining control and security.

In March, Norwich's population stood at 93pc of this capacity. Wayland and Bure were both operating at 99pc capacity.

Figures released last month showed that 296 assaults were recorded at Norwich in 2017, over double the number in 2012. Of those attacks, 83 were on staff.

The director of the Prison Reform Trust, Peter Dawson, said: 'Despite a virtually permanent programme of prison building, overcrowding has been an unchanging reality of our prison system since 1994. Building prisons isn't the solution - breaking our addiction to imprisonment is.'

Frances Crook, chief executive of the Howard League for Penal Reform, said last week: 'This shameful rise in violence and self-injury is the direct result of policy decisions to allow the number of people behind bars to grow unchecked while starving prisons of resources.'

A spokesman for the Ministry of Justice said: 'Prison numbers can fluctuate, which is why we have robust plans in place to ensure we always have enough prison places for those sent to us by the courts.

'We are investing £1.3 billion to build modern new establishments, with up to 10,000 new prison places and better education facilities.'