Locals now believe the artist has created the drawing to help with the campaign, although he has not yet confirmed the image is his despite it being similar to his style of work.
Some people have already taken to social media to guess whether it truly is the world famous Banksy backing their movement.
One Twitter user, said: “Very exciting to see Reading Gaol trending due to a possible #Banksy”
Another said: ““Could it be? #Banksy If so, that’ll really add some impetus behind the campaign to stop the redevelopment of Reading Gaol. #rdguk”.
The prison was first opened in 1844 but was shut in 2014 under the Closure of Prisons Order.
In 2015, the then chancellor George Osborne announced it would be sold as part of the Government’s spending review amid hopes more than 3,000 homes could be built on the sites of old ‘Dickensian’ prisons.
But since the closure announcement, calls have been made from nearby residents, the council and celebs such as Dame Judi Dench to save the building and make it a tourist attraction.
The award-winning actress said last year that it was “vitally important” the site was used in a way that “pays tribute to its artistic history.”
The plans to transform the prison into a cultural and artistic centre took a step forward last year after the Ministry of Justice (MoJ) said it would allow the council time to seek investment in the project, before it accepted any commercial bids.
An MoJ spokesperson said it had agreed a period of exclusivity until 15 March 2021, to allow Reading Borough Council to develop a business case with local partners.