Murals have been much in the news recently - well, one in particular has.
I mean of course the Banksy mural taken from the wall of Poundland in Wood Green, North London, which resurfaced last month at a little-known Miami auction house with an estimated price tag of between $500,000 and $700,000.
The mural, called Slave Labour, shows a small barefooted boy making Union Jack bunting in a sewing machine.
It was chiselled out of the wall by persons unknown before being shipped across the Atlantic for sale - only for the auction house, buckling under angry publicity, to withdraw it at the last minute whilst at the same time claiming there'd been "no legal issues whatsoever".
Who owned the mural?
Nicky Richmond, writing in the Times, has seen a copy of the Poundland lease.
As is often the case with properties like this one, the demise (what's included in the letting) is of the interior only, so the structure and exterior - where the mural was located - remain the landlord's responsibility.
So the image isn't owned by Poundland, and it seems the landlord's powers are sufficiently widely-drawn in the lease to have allowed it to remove the artwork if it had wanted to, although the Financial Times reported the owner hasn't commented on the sale and the Police have said there've been no reports of theft.
Is it owned by the landlord?
Well, the wall is, but the intellectual property issues surrounding the image itself are less clear cut - leaving aside the issue of criminal damage, does drawing something on someone else's wall mean you have assigned your ownership of the image to the wall's owner?
After all, you can't get the image back without carrying out more damage.
There doesn't seem to be a definitive answer to the intellectual property question.
Bad things often happen to murals as the Canadian Globe & Mail says: "exposed as they are to the elements, passersby and the hazards of being painted on an immovable wall... even indoor ones aren’t safe from misadventures".
They cite several examples, including two gigantic Picasso murals, damaged when the Oslo modernist buildings to which they are attached were damaged during the car-bomb part of Anders Breivik’s murderous spree in 2011.
And of course there's also Leonardo Da Vinci’s Last Supper in Milan, damaged by moisture, Napoleon’s invading troops, an aerial bomb during WW2, generations of bumbling restorers, and, one might add, association with a certain kind of...er...novel.
The Last Supper is actually a fresco, although font-of-all-wisdom wiki answers tells me that's just a particular type of mural distinguished by the way it's bound to the wall using fresh pigmentation - don't say you never learn anything useful here.
The 20th Century Society has launched a campaign to protect many of the UK's murals from destruction, for example when the buildings themselves are demolished.
Post-war murals are an endangered species, even though many of them are by celebrated artists such as Eduardo Paolozzi, Bridget Riley, Ben Nicholson, John Piper, Victor Passmore and Mitzi Cunliffe - as well as Banksy and others.
They are at risk too from weather, vandalism, changing fashions and commercial pressures.
First the murals need to be found and recorded.
Speaking on Radio 4's Today programme this morning, Catherine Croft, a director of the Society, talked about protection by listing as possibly being one option, although she admits that may be heavy-handed in some circumstances.
The Society wants to create a greater awareness and appreciation of murals generally and they ask people to send them images and information of any post-war murals they've seen.
The one I've used to illustrate this post is on the side of Archway Tavern, North London.
I think it brightens up an otherwise shabby corner, but as is often the case with murals, not everyone agrees.
Islington Council, in 2010, wanted it to be removed.