And on the flipside, his friend Tolkein would have written a very different Narnia series. The children of political criminals hiding out in an attic and wandering into Fantasy England to become fair, just rulers and overthrow a dictator? It's not just about Christianity, he's arguing for a better form of patriotism and Englishness and saying this is what we should have been and could be.
Even more significant considering the fact that Empress Jadis claims to serve the Emperor-beyond-the-sea/god and consider Aslan a "fraud" over being the son of god. It was obviously the author pointing out how the leadership of the New Entente has distorted Christianity for their twisted beliefs