Arsenal FC is facing a legal claim from a long-serving kitman who alleges he was dismissed due to social media posts expressing support for Palestine.

Mark Bonnick, 61, was at the centre of an online controversy late last year concerning his posts on X (formerly Twitter). He was dismissed just before Christmas after more than 20 years of service with the club.

Mr Bonnick claims Arsenal capitulated to online pressure from Israel supporters and subjected him to a swift disciplinary process, accusing him of bringing the club into disrepute.

He is now pursuing an employment tribunal claim, alleging unfair dismissal, and seeking reinstatement along with damages to restore his reputation.

He denies allegations of antisemitism and maintains that he became the target of an “online smear campaign” for expressing opposition to Israel’s military actions in Gaza.

“I was sacked not for misconduct, but for expressing grief and outrage over genocide,” he asserts.

“Despite being close to retirement, I have no regrets. Arsenal must apologise, reinstate me, and take a stand against anti-Palestinian racism.”

The case has been lodged at Watford Employment Tribunal and is expected to be fully heard next year.

Mr Bonnick states his opposition to Zionism, which he regards as a racist ideology, and argues that Arsenal treated him differently from other employees who might have posted about political views on other subjects.

His social media posts drew media attention in December last year. One read: “Hamas offered to release all hostages in October. Zionist Israel refused. Persecution complex.”

Another post from 7 December said: “Why should they be protected any more than any other community? Some see this as the problem Jewish communities thinking they should be put before others.”

Other posts included references to “Jewish supremacy” and “ethnic cleansing” amid online discussions about the Israel-Gaza conflict.

Following multiple news reports, Arsenal announced an investigation into the posts.

In his claim, Mr Bonnick refers to the club’s disciplinary findings that his comments “could be perceived as inflammatory or offensive” and that he had “brought the club into disrepute”.

He was found to have breached Arsenal’s social media policy and was sacked on 24 December. His appeal was rejected in February this year.

He contends that the dismissal was “disproportionate” and amounted to discrimination and harassment.

Representatives for Mr Bonnick claim he has been “punished for speaking out”. Tasnima Uddin, advocacy officer for the European Legal Support Center, which is supporting the claim, said: “Arsenal didn’t sack Mark for misconduct or antisemitism – they sacked him for standing with Palestine. This is political censorship.”

A protest in support of Mr Bonnick’s case is planned outside the Emirates Stadium on Sunday, ahead of Arsenal’s final Premier League home game of the season against Newcastle United.