"History has come full circle and Christianity is seen once more simply as one among a plethora of competing alternatives, all of which are regarded by an increasing number of influential intellectuals as dangerous," stated Oxford professor Dr John Lennox at this year's Keswick Convention.

"We are called upon to defend the Gospel. It is on trial, faith is under fire, and it is not only its contents, it is the messengers, and we will increasingly find we have not only to defend the Gospel to the world but we have to defend it to believers as well."

Under particular attack, he said, is "what Paul had to say about the cross and the death of Christ for sin".

Dr Lennox, who is a Reader in Mathematics at Oxford University, turned to claims of immorality made by prominent atheist Christopher Hitchens, and God Delusion author Richard Dawkins, who denounced such a theory as madness.

"The attack is under full sway and the intensity is increasing and we need to understand and remind ourselves that Paul, the apostles and Jesus Christ stand or fall together.

"We shall have to count the cost of what it means to defend historical Christianity."

Dr Lennox also spoke of a loss of confidence.

"A danger that I see is all around ... is a loss of confidence in God's word and its authority. We have to decide what side we are on and whether we are going to stand with Paul and the apostles and have confidence in the word and maintain the faith for which many of our forefathers stood."