Street artists are angry? They're people who paint shit on things they don't own? I didn't realize they had some sort of authority or claim to the city's walls and streets.

They're not the only ones who cover shit they don't own in London (or most world-cities for that matter), after all that's where Flyposters are paid for by taxpayers since the advertisers don't pay for the "media space" (which it isn't) and don't pay for it's removal. Some might argue that the spread of ads on 'pirated' space might have caused the street art boom as most artists paint over the illegal ads as canvas.
/serious ;)

It is pretty ironic though, and perhaps best summed up like Jordan said when Nissan did their Urban fakeout
I LOVE this, by the way. I love how how "legitimate underground artists" are pissed off that their idea of subversion is being subverted. And
it's probably the work of a street artist hired by a creative wonk like me at an agency to do the subverting.

"But, but, I wanna be angry! I wanna fight the power! I'm not just some whiney tagger bitching because, um, I get to decide what's cool and if you do something sort of cool-esque it erodes my cool and my identity as EDGY and SUBVERSIVE..."
Waaaaah!!!"

".....hijack an artform without investing in it."
They're just pissed because they aren't getting paid/rich.

...And these so-called "street artists" are idiots to boot! By getting their panties in a proverbial bunch about this and creating all this publicity, they're doing exactly the thing that Saatchi's intended: generating buzz.

The smarter move would've been to simply ignore the "fake art", thereby keeping it invisible to the masses...but they've played right into the publicity-creating trap...

..hehe, and they call advertising people manipulative. Gee, wonder why? ;))

I love this. Remember good readers