A few years ago a UK greeting cards company, Full Colour Black attempted to claim the trademark (and possibly copyright) for all of Banksy's work. They cited that as Banksy was claimed to have said, "Copyright is for losers" Banksy wouldn't put up a fight or stand up in court (and risk losing their anonymity).
In response, Banksy said,
‘A greetings cards company is contesting the trademark I hold to my art, and attempting to take custody of my name so they can sell their fake Banksy merchandise legally.’
Banksy did put up a fight, countering the claim and briefly opened up a shop, Gross Domestic Product, just to prove that he used his trademark. It seems Bansky won that round.
Now the guy behind the company that tried to get the Banksy trademark is at it again.
This time the card company owner is taking Banksy's company Pest Control Limited to court for defamation as the second defendant and the lead defendant being an artist called Robin Gunningham.
Personally, I hope this stunt stings them in the ass too.