How exactly did a fashion brand anger graffiti artist Banksy?

A person walks past the window display of a Guess store which includes the artwork "Flower Thrower" by artist Banksy on Regent Street in London. Photo: Reuters

Banksy has accused fashion brand Guess of using his work on a clothing collection without permission. The elusive artist posted an image of items on display in the window of Guess’s store on Regent Street in London.

He wrote: "Attention all shoplifters. Please go to Guess on Regent Street. They’ve helped themselves to my artwork without asking, how can it be wrong for you to do the same to their clothes?”