The correct response, Dave, is "What is yes"

It's funny you say that because I've had the exact same reaction to another composition of his with the same feature.  His painting, Don't forget your scarf/mummies boy punk, has hand painted wallpaper behind the stencils of the figures (which also have some hand paint but are largely stencil based).  I have wondered more times than I can count, why does a stencil based artist take the time to hand paint a feature that lends itself so easily to stencils?  Said differently, who hand paints the wall paper and then stencils the subjects?  Anyway, I don't have the answer but strange that he did so on that drawing you posted which was featured in the same (museum) show.  Come to think of it, he's always had a thing for wallpaper with the nice red backdrop in LA and that wallpapered elephant. 

Maybe he used a stencil, but used paint as opposed to spray for it?

They are done similarly but clearly painted freehand without a stencil as each is unique with variations to brushstroke (dots in some places, varying lengths and widths of lines in many others).  It's an interesting way of thinking to me to deliberately hand paint a repetitive background and yet cut stencils for the main subjects that dominate the viewers initial attention but that's exactly what he chose to do.  I'll post a link to a high rez photo below which you can expand and see for yourself if you wish.

Edit: Sorry, I suppose you have to copy and paste the link below but please add the letter "g" (so that the link reads .jpg) at the very end.  Each time I try to post the link here, it is instead posting the entire high rez photo in this thread and blowing out my response to moronic proportions. 

farm8.staticflickr.com/7447/10048014136_ebcaaccbe0_o.jp

>>>and his monkey in the tunnels<<<

Yup and he was using a fancy red wallpaper background as far back as turf war behind some of the vandalized paintings at that one. 

thx hnk, yeah that was the conclusion i came to (ie no win siutation). the reason i posted it was so that one could see that the background is hand painted which is pretty tough to do convincingly on anything outside of a high rez photo. The dimensions on that photo are manipulated and horribly out of whack too which you can easily see in the smaller size photo above. I corrected that one too quickly some time ago in i-photo and made a general mess of the painting when trying to use the straighten function so it appears smaller towards the bottom and larger at the top. Anyway, you can see the background easier in that one but that's about all that particular photo is good for. My apologies

Didn't know Banksy was a rugby fan.  Good to see Mako Vunipola represented in his work though

The birdcage with pink tag and the pink 'composit...' Rule. Very nice indeed!

Yep...

Any chance you have an unobstructed pic of that lage piece?

Much appreciated and good work! 

Just read through most of this thread. Some great photos posted over the years! Especially dug those sketches on the first page!