Updated

A London neighborhood wants its Banksy back.

A stencil by the famed but secretive graffiti artist of a young boy sewing Union Jack bunting on an antique sewing machine appeared on the side of a north London bargain store last May. Soon the gritty Turnpike Lane area was drawing art lovers keen to see Banksy's typically cheeky take on the Diamond Jubilee celebrations of Queen Elizabeth II's 60 years on the British throne.

Last week it vanished, leaving nothing but a rectangle of exposed brick -- only to reappear on the website of a Miami auction house. Listed as "Slave Labor (Bunting Boy)," it is due to be sold Saturday with an estimated price of between $500,000 and $700,000.

London authorities concede the sale is probably legal -- the mural was on private property. But they hope moral pressure will make the auction house change its mind.

"(It's) totally unethical that something so valued should be torn without warning from its community context," local lawmaker Lynne Featherstone said.

Featherstone said she had asked the building's owner for an explanation, but had yet to receive a reply. Poundland, the store that occupies the building, said it had nothing to do with the removal.

On Wednesday, the local government authority appealed to the auctioneer for the return of the work.

In an open letter to auction house chief Frederic Thut, Haringey Council called the artwork "a much-loved local landmark" that had been visited by people from around the world.

"We understand that there may be nothing illegal in the way this artwork was quietly removed from our streets and put up for auction by you in Miami," the letter said.

"But for you to allow it to be sold for huge profit in this way would be morally wrong, and completely contrary to the spirit in which we believe it was given to our community."

Councilor Alan Strickland said the work had become "a real symbol of local pride" in an area badly hit in England's August 2011 riots. He said its disappearance had left residents "shocked and angry."

Strickland said he had asked England's Arts Council for help retrieving the work.

The government-funded council called the loss of the Banksy "a shame," but said there was little it could do. The council has the power to stop the export of culturally significant artworks, but only if they are more than 50 years old.

Fine Art Auctions Miami said it had acquired the work legally, but gave few other details. It said in a statement that it had "done all the necessary due diligence about the ownership of the work."

"Unfortunately we are not able to provide you with any information by law and contract about any details of this consignment," it said. "We are more than happy to do so if you can prove that the works were acquired and removed illegally."

Banksy's publicist did not immediately reply to a request for comment.

The anonymous street artist, who refuses to reveal his real name, began his career spray-painting buildings and bridges in his home city of Bristol in southwest England. His often satirical images include two policemen kissing, armed riot police with yellow smiley faces and a chimpanzee with a sign bearing the words "Laugh now, but one day I'll be in charge."

Original Banksy works now sell for up to hundreds of thousands of dollars and the artist has become an international celebrity. He has created sequences for "The Simpsons" and directed an Academy Award-nominated documentary, "Exit Through the Gift Shop."

His works are still sometimes obliterated by zealous local officials, street cleaners or -- as in this case -- taken off buildings along with a chunk of wall for private sale.