Manchester, like all cities, has its share of graffiti. While much of it is the usual tribal markings, the City Council has always encouraged street artists to decorate whole swathes of the city.
The Northern Quarter, the centre of the old cloth making industry, has been undergoing gentrification for some years. The Council decided that public art was a way of encouraging the transformation of the area into a funky area attractive to young residents, artists and businesses.
Even new developments have bought into the idea of writing on walls.
The beauty of graffiti is its strictly temporary nature. I think you’d be hard pushed to find these examples still in situ (apart from the apartment block!)