Victor Kennedy, 37, was held in solitary confinement for more than 50 days after an incident in March before being moved to another wing, according to Madden & Finucane Solicitors.

Lawyers acting for Mr Kennedy confirmed he was exercising a “dirty protest” during this time.

He went on to issue judicial review proceedings against the Northern Ireland Prison Service.

Ruling on the case, Lord Justice Weatherup declared that Rule 32 of the Prison and Young Offenders Centre (Rules) Northern Ireland requires the Prison Service to notify the Independent Monitoring Board of any incidents of prisoners being placed in segregated conditions, including for prisoners exercising a dirty protest.

A further declaration was made that Mr Kennedy was unlawfully segregated for a period of time without any proper authority.

However, the judge rejected claims that Mr Kennedy should not have been suspected of involvement in the assault which was used to justify his segregation.

Katie McAllister of Madden & Finucane Solicitors said: “This case highlights the failures of the Prison Service to properly apply the Prison Rules in cases where prisoners are subjected to the most draconian measure of solitary confinement.

“Once again this raises serious concerns about the current state of the Northern Ireland Prison Service, as illustrated in the recent CJINI report on the unannounced inspection of Maghaberry Prison.”