Aaron Barschak, the self-proclaimed 'comedy terrorist', could be jailed for throwing red paint over Turner Prize nominee Jake Chapman and one of his paintings.
Barschak pleaded not guilty
Barschak, 37, from Golders Green, north London, claimed he was collaborating with the artist and denied causing criminal damage at the Modern Art Oxford gallery on 30 May.
On Thursday, Oxford Magistrates Court found him guilty of criminal damage and he was told to expect a custodial sentence.
District Judge Brian Loosley said: "I may well want to pass a custodial sentence to reflect my displeasure."
Mr Loosley said: "This is a serious offence of wanton destruction of a work of art and I will be considering a custodial sentence.
"I am not prepared to tolerate damage to works of art in Oxford or anywhere
else for that matter.
"I feel that this was a publicity stunt and not a genuine attempt by you to
create a work of art.
"In the course of your publicity stunt, you caused substantial damage to the
painting, to the gallery, the floor and the walls."
The judge adjourned sentencing until 24 November for pre-sentence reports.
The paint attack happened during a private talk about Mr Chapman's work to the patrons of the gallery.
In police interviews after his arrest, he said he had "incorporated" Jake Chapman into a work of art of his own, adding: "I painted him."
When asked why he had thrown the paint, he replied: "I would rather you say I painted rather than I threw the paint."
He added: "It's an improvement on Mr Chapman's painting and it's an
improvement on the wall as well."