Rule breakers at Whitemoor Prison in March are locked in cells as punishment
Inmates were locked in their cells for 100s of days in just three months for breaking rules at Whitemoor Prison, according to Ministry of Justice data.
The Howard League for Penal Reform say punishing inmates with confinement contributes to worsening conditions in prison.
Inmates at the March prison committed 259 proven offences between July and September, of which 42 resulted in the culprit being confined to a cell.
The offending prisoners received 378 days of confinement - the equivalent of a year between them.
HM Prison and Probation Service guidance states that adult prisoners can be confined to their cells for up to 21 days for a single offence, with young offenders getting up to 10 days.
Prisoners at Whitemoor were most likely to be confined in their cells for non-violent offences, with 37 incidents over the three-month period.
Of these, 12 were for disobeying a direct order or breaking prison rules, for which the offenders spent a total of 105 days locked in their cells.
A further nine inmates received 84 days in confinement for possession of unauthorised items, which could be anything from weapons to mobile phones.
Long periods of cell confinement can cause the mental and physical health of prisoners to deteriorate, according to HM Inspectorate of Prisons.
In a 2017 report, the Inspectorate said it was also concerned that many inmates were spending up to 22 hours in “unpleasant” cells, worsening the impact of extended confinement.
Offenders can be sent to a designated segregation unit, but are often locked up in their own cells.
Howard League chief executive Frances Crook said: “Prisoners punished with confinement will have their things taken away and are locked up with no stimulation.
“If there are cellmates involved, that creates a lot of resentment and tension, since taking away things like TVs and radios effectively punishes them as well.”
The Howard League said it recognises that sanctioning rule breakers is necessary, but said an incentive and praise-focused system would be more effective.
Ms Crook added: "Justice is not a synonym for punishment. Prisons should be trying to create hope for the future, rather than trying to punish their way out of problems.”
An HM Prison Service spokesman said: “It is right that governors who know their prisons best have the freedom to decide how to deal with those who break the rules.
“We are reviewing the existing disciplinary processes as part of our wider programme of prison reform.”
Across England and Wales, nearly 7,000 incidents over the three month period resulted in almost 50,000 days of confinement - the equivalent of 130 years locked up.