parris converted?

Matthew Parris, former Tory M.P. and journalist for The Times, has written an article in which he argues that what Africa needs is Christianity. What makes this piece so surprising is that Parris is an atheist and yet he declares:

Now a confirmed atheist, I've become convinced of the enormous contribution that Christian evangelism makes in Africa: sharply distinct from the work of secular NGOs, government projects and international aid efforts. These alone will not do. Education and training alone will not do. In Africa Christianity changes people's hearts. It brings a spiritual transformation. The rebirth is real. The change is good.

You can read the full article here. Parris puts forward a convincing case, however, the question I would like to ask him is this:

If Christianity is the answer for Africa then why isn't it the answer for Great Britian and why isn't it the answer for Matthew Parris?