LONDON: A man convicted of terrorism offenses won a legal challenge against the British government on Tuesday for being unlawfully held in segregation for 22 hours a day after prison guards were attacked by another terrorism inmate.

Sahayb Abu, who is serving a minimum 19-year prison term for planning an attack in Britain, took legal action against the Ministry of Justice.

He was one of several prisoners who were segregated after Hashem Abedi, the brother of a man who detonated a suicide bomb after an Ariana Grande concert in Britain in 2017, attacked prison guards in April at Frankland prison in northern England.

In response, Abu – who had previously been put in a separation center over concerns he could radicalize fellow inmates – and other people convicted of terrorism charges were relocated and put under strict segregation measures for staff safety.

Abu, who had pre-existing mental health issues, was locked in his cell for more than 22 hours per day and not permitted to associate with any other prisoner for more than four months, his lawyers told London’s High Court.