A West Ham supporter who wore an anti-board T-shirt while volunteering as a pitchside flag-waver before last week’s game against Liverpool at the London Stadium has been banned by the club from attending any of their matches for the rest of the season.

Cameron Robson took the opportunity to protest against West Ham’s beleaguered board when he volunteered to wave a giant club flag before Liverpool’s 2-0 win. Robson, a season-ticket holder, unzipped his jacket to reveal a T-shirt with the message “GSB OUT” – a reference to the club’s co-owners, David Gold and David Sullivan, and the vice-chair, Karren Brady. He had passed through stadium security while wearing the top under his jacket.

Robson has received a letter from West Ham telling him that “your display of provocative messaging was deliberately intended to incite the crowd”. The letter says that he breached regulations prohibiting the presence within the ground of anyone “who is or could (in the Operator’s reasonable opinion) constitute a source of danger, nuisance or annoyance to any other person”.

West Ham, who are facing growing unrest from supporters, went on to tell Robson that his account had been suspended, that he is banned from entering the London Stadium and that he cannot attend any West Ham fixtures or events for the rest of the season. He has the right to appeal and indicated that he intended to do so.

Robson told the Guardian: “I don’t think it’s fair. They see me as a source of danger, yet LS185 [the stadium operators] allow a protest to happen on their grounds. I’m not surprised it happened. It’s the board so can 100% expect it coming. However, it’s quite a low blow from them. Not much they can possibly ban me for.”

West Ham are 18th in the Premier League and Sullivan, Gold and Brady are under increasing pressure from an unhappy fanbase. Between 900 and 2,000 West Ham supporters held a static protest against the board before last month’s 1-1 home draw with Everton and further demonstrations are planned this month.

Hammers United, an increasingly influential fan group, plan to release black balloons from the away end when West Ham visit Liverpool on 24 February and are organising another protest before Southampton visit the London Stadium on 29 February.

West Ham declined to comment.