According to Peter Mullen here:

Richard Dawkins says that David Cameron is “not really a Christian”. The fact is that it is only God to whom all hearts be open, all desires known and from whom no secrets are hid. So Dawkins has no means of telling whether Cameron is a genuine Christian or not.

We can, however, know that Dawkins is not a proper atheist – that is an intelligent atheist – from his own puerile writing and pathetic attempts at philosophical theology. For example, he writes: “Either God exists or he doesn’t. It is a scientific question. The existence of God is a scientific question, like any other.”

This is idiotic. Science investigates material phenomena, observable entities in the universe. No competent theologians or philosophers – not even the atheist ones – have ever declared that God (if he exists) is an object in his own universe. Perhaps there is no God, and intelligent Christians readily admit that there may be some legitimate doubt. But if the Judaeo-Christian God exists, then he is the maker of the universe and not an entity within it.

That is why science can make legitimate pronouncements on whether bigfoot, fairies, flying spaghetti monsters – and even Greek gods who were believed to be a part of the natural universe – exist, but not God the Creator, whose actuality is independent of his creation.