The BBC was tricked into showing a homemade tinfoil copy of the FA Cup emblazoned with the words “Fuck the Tories”.
The slogan was hidden under a flap of the replica during the FA Cup home clash between Wrexham and Sheffield United.
Hollywood stars Ryan Reynolds and Rob McElhenney own the Welsh club.
A shot of the political slur flashed up on the BBC’s live coverage of the game – which ended in 3-3 draw.
It is the second time the same message has been seen at the Racecourse Ground.
Last October striker Paul Mullin was banned from wearing his new botts after he posted a message showing “Fuck the Tories” was printed on the side.
At the time Wrexham said the club held political allegiances.
A statement said: “The club has adopted a neutral position on many matters with a political dimension and intends to continue to do so going forward.”
Commenting on his team’s performance, Reynolds said he was “proud of that he’d seen”.
Wrexham is the only non-division side left in the Cup.