In a letter to Prof Dawkins, Dr Came said: “The absence of a debate with the foremost apologist for Christian theism is a glaring omission on your CV and is of course apt to be interpreted as cowardice on your part.

“I notice that, by contrast, you are happy to discuss theological matters with television and radio presenters and other intellectual heavyweights like Pastor Ted Haggard of the National Association of Evangelicals and Pastor Keenan Roberts of the Colorado Hell House.”

Prof Craig, however, remains willing to debate with Prof Dawkins. “I am keeping the opportunity open for him to change his mind and debate with me in the Sheldonian Theatre in Oxford” in October, he said.