There are numerous graffiti removal systems available throughout the UK. Most of these either rely upon abraisives (which simply remove graffiti by removing the surface of the substrate the graffiti is on!), strong or aggressive chemicals (melting Perspex bus shelters and damaging reflective road signage for example) or simply rely upon very high pressure water. The only way that high pressure water will ever remove graffiti from a porous surface like brickwork or concrete is by removing the surface of the brick itself!!