It is quite remarkable that TfL started promoting riding bicycles in this way.
It's stylish, establishes bicycle as a fashinable mean of transport and shows normal people riding it. No more of this lycra rubbish. Ladies riding in their skirts men rolling up their trousers (well they haven't thought about full chainguards yet!). I think it's the usuall strategy of TfL to show some of people riding bikes with and some without helmets, which points out to the freedom of choice to wear them. Good on them.
The campaign also suggests that people pick up riding on their bikes when seeing other people/collegues doing it. It so happens that most people cycle, where they have good infrastructure. Go figure...