Phlegm is a local graf artist - I've seen his work dotted around Sheffield here and there, and I showed a shot of one small piece that's now sadly lost.
This bigger piece is really superb, its on the wall of a Sheffield pub which overlooks a river. You can see how the masts on the boat are placed to tie in with the wall structure overhead.
I don't know the history of it, whether it was done with the approval of the owners - maybe it was as it is such a part of the Pub wall - I could google it but in fact I don't care why its there or how it got there, only that it is there :)
I just love this piece it has so many different facets . . .