An independent councillor suspended for three months in a row over flags has lost his legal battle to overturn the sanction.
Senior judges ruled that Padraig McShane has exhausted appeals against being denied the right to challenge the decision.
In 2015 he was pictured with the Irish tricolour and a Palestinian flag at Causeway Coast and Glens Borough Council’s Coleraine headquarters.
Alongside him in the photograph were Londonderry-based independent councillors and visiting Gaza official Mohamed Al-Halabi.
A DUP representative lodged a complaint after the picture emerged.
In November 2016 the Northern Ireland local government commissioner for standards ruled that Mr McShane had breached the council’s code of conduct.
He was banned from all council meetings for a three-month period.
The adjudication covered a prohibition on the use of position to confer and secure personal advantage, and the use of council resources “for political purposes”.
Mr McShane did not attend the hearing where the sanction was imposed.
His legal team challenged the suspension on the grounds of his right to freedom of political opinion.
They contended that the councillor is entitled to free speech under Article 10 of the European Convention on Human Rights.
A High Court judge refused to grant leave for a challenge to the decision after concluding that the sanction was proportionate.
Lawyers for Mr McShane contested that determination, claiming it involved an error of law.
But the Court of Appeal rejected submissions that the councillor had been deprived a hearing.
Lord Chief Justice Sir Declan Morgan said: “The applicant had every opportunity to engage with the investigative process but chose not to do so.
“He cannot now complain that he needs a further opportunity to be heard.”
Dismissing the challenge, Sir Declan added: “We wish to emphasise our support for the proposition that the courts should be careful to protect the right of politicians to exercise their right to freedom of expression.
“Any justification for interfering with that right must be carefully scrutinised.”