LONDON — It is not unusual for works of art to be lost and then found. It is rarer when the piece is painted on the side of a building.

But that is the case for a Banksy stencil, “Snorting Copper,” on the site of a former public toilet in the Shoreditch area of East London.

Five years ago, Jonathan Ellis, a property developer, heard rumors that a lost work by the mysterious graffiti artist known as Banksy was hidden under a layer of paint on a brick wall in a weed-choked plot.

Two years ago, Mr. Ellis, by then the founder of Hamilton Court Developments, was able to buy the site on Curtain Road to convert it into a commercial and residential space.

Eager to see if the rumors of a hidden Banksy were true, he wasted little time.

On the day he got the keys to the site, Mr. Ellis said, he had plywood that had been screwed to the wall removed, but “it wasn’t one of those eureka moments where we pulled the ply off and oh my god there it was.” read more