Why is Great Britain so atheist?

It seems that Great Britain is very atheist, with native sons like Richard Dawkins, Christopher Hitchens, Ricky Gervais, etc. I want to know what cultural factors contribute to this. I want real, thought out answers NOT smart aleck remarks like "Britons are smarter" or "British schools aren't very good" I want to know what is causing this trend. Does the Church of England have anything to do with this. Does it have to do with the liberalization of the C of E? Is it more secular than the rest of Europe? Is this just a European thing a American wouldn't understand? I am asking this purely because I am curious. Thanks for your answers in advance!!!