A recently made mural by Banksy on the side of Reading prison has been vandalized with red paint and the graffiti tag of a rival artist. And this isn't the first time it has happened.

The mural, entitled Create Escape, which Banksy made earlier this month, depicted a prisoner scaling the wall using a sheet tied to a typewriter. This week, photographs emerged that showed the piece had been defaced with red paint covering the typewriter, with the phrase “Team Robbo” below. This is a reference to the late graffiti artist King Robbo, who was widely regarded as Banksy's greatest rival. Their long-running feud is believed to have begun in 2009 when Banksy painted over one of Robbo’s tags by Regent’s Canal in London.

In response to the vandalism of Banksy's work, Save Reading Gaol (a campaign to turn the former prison into an arts and culture center) tweeted yesterday: "Awful news to wake up to and to realize that the failure to protect something precious to the town has left it vulnerable to destruction."

Create Escape was created overnight on 28 February and was officially confirmed as a Banksy on 4 March, when the elusive street artist posted a video on his Instagram account. The video, a parody of The Joy of Painting with Bob Ross, shows Banksy prep and execute the painting in the form of an instructional art video.

The mural is believed to be a reference to Oscar Wilde, who served two years’ hard labor at the prison after being convicted of “committing acts of gross indecency” – homosexuality – in 1895. Although the site closed to prisoners in 2013, its future has been the focus of fierce debate, with local campaigns fighting to turn the former prison into an arts hub. With Create Escape, Banksy seemingly threw his weight behind those plans.

While the mural's vandalism is a shame for activists in Reading, this isn't the first time Banksy's work has been attacked. Similarly, in December, two Bansky murals in New Orleans were tagged with messages about King Robbo.