Emma B. -

No, Britain hasn't "always" been Christian anymore than the Middle East (for example) has 'always' been Muslim. But in both cases, the relevant faith played a crucial role in the evolution of culture and institutions. Quite a bit has happened in the last 1500 or so years, don't you think?

As for the pagan stuff, it used to be fashionable to look for pagan survivals in British folk music, dance, etc., but most of these claims never really panned out.

(I remember once, as a child, watching the Boston Celtics playing basketball on television. I asked my uncle, "Who are the Celtics?" He answered, "The Celts are your ancestors." "These guys are my ancestors," I thought, with a sense of wonder and bewilderment.)