It depends on the town a bit I think. In Brighton there are lots of small business and some areas have no chains at all. Not sure if that is because of planning policy or for another reason.
That's very definitely the result of both council and cultural factors. Brighton is special.
Mind you, so are a lot of other places. I see from http://www.rudi.net/node/22184 that Cambridge is very clone-ridden, which feels about right. It's an odd collision between architecturally interesting colleges and medieval street layout on the one hand, but an almost total lack of properly local shops due to high costs. Since the takeover of Heffers and Eaden Lilley the only one I can think of is Mackay's.
