A Banksy mural which survived the elements on a sea wall since last summer has been defaced by graffiti.
An image of hermit crabs, with one holding a sign stating "Luxury rentals only", appeared in Cromer, Norfolk, in August.
At the weekend, a large section of the wall, including the Banksy artwork, was sprayed with paint. The graffiti has since been removed.
Norfolk Norfolk District Council called the vandalism "hugely disappointing".
The hermit crabs were part of the artist's "Great British Spraycation", during which several works cropped up in Norfolk and Suffolk and were confirmed as Banksy's.
The mural was given a weatherproof protective coating last summer and it is understood it has not been damaged by the spray paint.
Steve Hobart, who photographed the graffiti on Saturday, said it was "unbelievable".
"A priceless Banksy and the work of another unknown artist," he posted on Facebook, with the hashtag #idiots.
It is not the first time a piece in the series has been sabotaged.
Soon after it appeared, a rat reclining in a deckchair on the sea wall at Lowestoft was painted over, and in January, an offensive message was left on the protective plastic covering Banksy's arcade-style toy grabber in Gorleston-on-Sea.