The head of the Police Service of Northern Ireland is facing mounting pressure to quit after a court ruled that the force unlawfully disciplined two junior officers to placate Sinn Féin. Unionist politicians said on Wednesday they had lost confidence in Simon Byrne, the PSNI chief constable, and urged him to resign. A special meeting of the Northern Ireland Policing Board, which oversees the force, will take place in Belfast on Thursday, where Byrne will be questioned over the matter. The controversy follows a separate crisis earlier this month over data breaches involving the personal information of more than 10,000 officers and support staff. The latest blow to Byrne’s leadership came on Tuesday when a high court judge, Mr Justice Scofield, ruled that the PSNI unlawfully disciplined two officers over their policing of a republican commemoration in Belfast in February 2021 during Covid-19 restrictions. The officers briefly detained and handcuffed a man on suspicion of disorderly behaviour during a wreath-laying ceremony at the scene of a loyalist gun attack that killed five Catholics in 1992, prompting furious protests from Sinn Féin. Byrne apologised and the PSNI suspended one constable and repositioned the other. A high court judicial review brought by the two officers, who were backed by the Police Federation, quashed the PSNI’s actions. “I have been persuaded that the respondent imposed suspension in the first applicant’s case because of the threat (whether real or perceived) that if it did not do so, republican support for policing would be withdrawn,” the judge said. “To reach a decision on that basis was in my view unlawful.” Byrne accepted that the force had made a legal error. “We will of course take time to carefully consider the full judgment to ensure any lessons are learned to prevent any future recurrence,” he said. Trevor Clarke, a Democratic Unionist party member of the Policing Board, said Byrne should quit. “The only option open to Simon is to resign,” he told the BBC. “Where a judge has said a chief constable is prepared to sacrifice his young officers, how can the chief constable or anyone else expect their support or anyone else’s support.” The Ulster Unionist party leader, Doug Beattie, said the positions of Byrne and other senior PSNI managers were untenable if they had taken action against two constables in response to a threat from a political party. The Traditional Unionist Voice leader, Jim Allister, called on Byrne to go. “This is a staggering indictment of the chief constable and a sobering insight into the politics of keeping Sinn Féin happy at all costs.” Westminster’s Northern Ireland affairs committee is expected to question Byrne on 5 September over the data breaches.