A man appeared on the BBC’s Antiques Roadshow this weekend hoping to score a favorable appraisal on a unique piece of art: a rat stencil on a steel plate, purportedly painted by Banksy.

The segment did not go as he hoped.

The owner, who went unidentified, claimed to have spotted the piece on a seaside wall around 2004, when he was living in Brighton, England.

“It looked loose,” he said during the show. “[I] went over, pulled it off basically.”

“Gave it a little persuasion?” the show’s specialist, Rupert Maas, nudged winkingly before abruptly changing tone. 

“The thing about Banksy,” Maas said, “is that he manages his brand very, very carefully indeed.” He explained to the man that Banksy operates a website called Pest Control that allows potential owners of his work to apply for a certificate of authenticity, which the artist will give should the piece in question indeed be real and not removed from the public domain. 

The man said he had applied for such a certificate but was denied.  

“I think the message here is that, if you do see a piece of graffiti art out there, leave it, leave it for the public,” Maas said in a manner reminiscent of a not-angry-just-disappointed dad. “I’m not lecturing you. I’m just saying, without that certificate, it’s just very difficult to sell. With it, it might be worth £20,000. Without it, you’re nowhere.”

Under a Pest Control FAQ section explaining the authentication process, a line has been added to say “The Antiques Roadshow sums it up rather well,” with a link to the segment clip. 

On social media, users promptly roasted the owner like a butternut squash. Others suggested he might have been a shill hired by Banksy himself to prove a point. (In 2011, the artist directed a documentary film about activist pranks called The Antics Roadshow.)

A representative for Banksy did not immediately respond to Artnet News’s request for comment.