SIR - Graffiti can be awful and I reported a racist piece of graffiti to West Yorkshire Police last year. But sometimes it can be artistic and brilliant.

Even on the short train journey from Saltaire to Bradford, I see some astonishing bits of art work and imagery on freight trains, walls and old buildings.

First question is who? Never see them doing it and it's everywhere. Then why? But most of all, how? On motorway bridges and tops of office blocks, how did they get there?

Alan Bates, Coach Road, Baildon