An artwork by acclaimed street artist Banksy that appeared on a public toilet block in east London, only to disappear after it was vandalised, has been rediscovered over a decade later, the media reported.

Known as the “Snorting Copper” and considered an exemplary image by the elusive graffiti artist, it shows a uniformed policeman on his hands and knees snorting a line of cocaine, reports the Guardian.

Although the painting has been valued for insurance purposes at 1.25 million pounds, Jonathan Ellis and David Kyte, who uncovered the painting after they bought the disused site, said they have no intention of selling it.

Instead, they are restoring it and will return it to its original site in Shoreditch, Hackney, so that the general public can see it. The unveiling will take place on October 5.

“It’s an amazing piece,” Ellis told the Guardian. “We’ve had offers to sell it. But we want to put it back. We think that’s the right thing to do for the public to enjoy it. I’m proud to be able to do something like that.”

John Brandler, a specialist dealer in Banksy artworks, said the painting was a famous image, reproduced in several books, “but no one knew where it was”.

Other Banksy works have been vandalised or destroyed.

In 2014 a Banksy artwork in Clacton-on-Sea depicting pigeons holding anti-immigration banners was removed by the local council after someone complained it was racist.

Banksy, known for his stencil-based images, has maintained his anonymity, despite repeated attempts to unmask him. Describing himself as a “quality vandal”, he has made his name by poking fun at authority figures through artworks in public places, the Guardian reported.

Stencil enables him to work at speed, quickly disappearing into the night.

In 2005, he smuggled his own works into major museums including Tate Britain in London and the Metropolitan Museum in New York. In 2015, he opened Dismaland in Weston-super-Mare, a temporary amusement park and conceptual art show.

In July, his “Girl with Balloon” – in which a child watches her heart-shaped balloon drift away – was voted Britain’s best-loved work of art.