The rare original flyer advertising the unveiling of Banksy's 'Our Lady of Justice' sculpture on Clerkenwell Green in London.

The sculpture, weighing 3.5 tonnes (3,500 kg), was secretly installed in the early hours of Wednesday 4th August, 2004, and the unveiling was attended by hundreds of people later the same day.

Banksy's version of the lady (the original of which overlooks the Old Bailey, the Central Criminal Court of England and Wales, in London) has US dollar bills stuffed into her garter, thigh length PVC boots, hitched skirt revealing thong and a blindfold, with a plaque on the plinth saying: "Trust no-one."

"This is a brand new monument for London," Banksy wrote in a statement read out by rapper MC Dynamite.

"It is a monument dedicated to thugs, to thieves, to bullies, to liars, to the corrupt, the arrogant and the stupid."

He said the stunt was timed to coincide with the first anniversary of the death of Kevin Callan, the lorry driver who was the victim of a miscarriage of justice when he was convicted in 1991 for the murder of a four-year-old child (his conviction was overturned in 1995).

"It's the most honest depiction of British justice currently on display in the capital," Banksy said. "I hope it stays there for good. We are learning that the people we trust with our liberty cannot be trusted."