‘If he can’t be in politics,’ the Archbishop of Canterbury tweeted last week after Tim Farron resigned the leadership of his party, ‘media & politicians have questions.’

So prelates now think complex theological concerns can be despatched within the Twitter limit of 140 characters. They cannot. Let me now unpack Dr Welby’s abbreviated consideration of this subject and examine what’s behind it, because the subject is of profound importance —and not only for Christians.