Art or criminal damage?

Hello fellow bloggers firstly apologies for the lack of posts recently. I don't really have a reason just had nothing to say. However recently something or someone has come to my attention. Namely a graffiti 'artist' from Bristol by the name of 'Banksy'.

I don't know if any of you are already familiar with this persons work or not but lately I have seen his work at least Banksy inpired works appearing in my city.

Recently he has been auctioning his work off for tens of thousands:

On 7 February 2007, Sotheby's auction house in London auctioned three Banksy works and reached the highest ever price for a Banksy work at auction of over £102,000 for his Bombing Middle England. Two of his other graffiti works, Balloon Girl and Bomb Hugger, sold for £37,200 and £31,200 respectively, which were well above their estimate prices.The following day's auction saw a further three Banksy works reach soaring prices. Ballerina With Action Man Parts reached £96,000 whilst Glory sold for £72,000 and Untitled (2004) sold for £33,600 - all three auctions sold way over expected estimates. To coincide with the second day of auctions, Banksy updated his website front home page with a new image of an auction house scene with people bidding on a picture that said, "I Can't Believe You Morons Actually Buy This Shit."

Here is a selection of my favourites. More can be found here.

So is it art or criminal damage????