Although it may not be limited in scope purely to Greater London in the 1980s, there is a thing that one sometimes spots on walls, usually in the vicinity of 'social centres' of one sort or another, that can only be described as the GLC Mural. A genre pioneered by the municipal socialism of 'Red' Ken Livingstone (ah, the irony), whereby a given area of street would be 'improved' by having a mural painted on it: a typical one in New Cross features Margaret Thatcher, Ronald Reagan and one of the short-stay geriatric Soviets (Andropov or Chernenko) riding atop nuclear missiles, in a painted analogue to the 'Two Tribes' video and a hundred Ben Elton jokes. They're really rather sweet, and in their way give the effect of London as a garrison town of antiwar, anticapitalist sanity in a sea of militarism and rapacious capital, which seems faintly preposterous in retrospect.
This sprang to mind on reading of how a favela in Rio has turned itself into a temporary art gallery (more here), essentially by painting onto the walls of the various shacks. This could easily be dismissed as an ultimate example of window-dressing poverty via 'creativity'- that the favelas might be less poor and violent if Freize send a few people over to review the hut facades- and the involvement of a Dutchman called 'Koolhaas' (not the same one mind you) in the planning of the painting programme would reinforce this proposition. Nonetheless, there is something quite promising here. The siedlungen of Red Vienna grew out of the shanty towns on the city's outskirts, and yet the equivalents today of an Adolf Loos who would play architect to the favela tend to spend more time awed at the 'vibrancy' and 'diversity' of the 'community' to actually do anything that might involve making the environment less horrible for its inhabitants. Any intervention in the alltagsleben of the 21st century proletariat for transformative purposes would seem to have some at least symbolic value, even if involving patronising but well-meaning Koolhaases.
It's always as an imposition of some sort however- note the difference between this and the actual environment creation of many of the locals- ie, painting your own personal Logo around the place (I did see the spray paint-covered Camden tube station around Christmas that caused so much controversy- my reaction being a combination of 'how incredibly pointless' and 'er, well done'). None of this has any of the peculiar charm of the murals in the Sicilian town of Orgosolo, where from the 70s, pseudo-Picasso depictions of Gramsci or Lenin appeared on the sides and corners of the picturesquely dilapidated dwellings, and where libellous commentary on Italian politics and admonitions to be nice to the elderly are the manner of urban decoration, rather than the endless wildstyle variants on 'I was here'.