A friend, John Davies (who is a retired Anglican bishop), writes
I find myself often thinking of texts and statements as 'windows' into situations; most obviously true of the NT Letters and the various episodes in Acts. Incomplete, but, we affirm, sufficient (today's BBC news is making quite a thing of the 'Gospel of Judas', as if this would cause us to revise the creeds. The funny thing is that, to be an orthodox (in the general sense) Christian, you dont have to believe anything much about Judas. The Arrest would have easily happened without him. He is important, not because he is essential to the story but because his presence in the story re-assures us that betrayal is part of the normal environment of the Christ-presence and therefore we shouldn't be surprised when it happens to us, through us, or by us. Every priest is a betraying priest, and I find that I still catch my breath at the point in the Canon where I have to say 'in the same night in which he was betrayed)
Anyway, this blog has some more on it, and a link to a translation of the text.
Deus Creator Omnium