Peter J. Williams is the Warden of Tyndale House, Cambridge.
Regarding the authorship of John and comparison of Biblical attributions of authorship as compared to that of other writings from antiquity, Peter says in this interview:
[I]n the case for John’s Gospel, the evidence for it being by John is particularly strong, because we have Irenaeus in the last part of the 2nd century, who clearly has the fourth Gospel in front of him, he quotes from it, there’s no doubt about that. Saying that it really was by the John who he’s only two steps removed from. He had met Polycarp, who had been a disciple of John, so he’s really quite close. That’s far better attestation than we have for a huge number of classical works whose authenticity we don’t doubt. So if you think about Plato and so on, it’s not that we have someone two steps away from Plato reading a bit of a title of one of Plato’s dialogs and saying, ‘And I have the book in front of me’, and it’s the same person. Actually, the way we work out classical authorship is a lot more based on inference.
[F. F. Bruce] compares the number of manuscripts we have of the New Testament with those we have on classical works. The structure of his argument is to say, ‘Well, people accept the validity of classical works, therefore, by consistency (to be consistent), they should accept the validity of the New Testament, because it’s got far better attestation’. That’s to work from a premise that people already accepted—namely, the classical works are broadly correctly transmitted—to establish another premise. That’s very different from saying, ‘The New Testament is better than the classical works ’cause it has more manuscripts’, because that isn’t involved in establishing premises at all.
Here is a list of other Scholars with an Appreciation of Textual Criticism for Classical as well as Biblical Literature