Here is a testimony by Antony Flew himself on his belief in a deist god.
He is not a christian yet, although I pray that he may come to know Christ! He was one of the world's leading atheist philosophers and changed his mind, he is now a believer in a deistic god.
He has participated in many debates with people including C.S. Lewis and many others.
To find out why he changed his mind then watch the following:
(1 part, approx 2 minutes)