Mr Gummer sits on the edge of the pink armchair in his large office in the Ministry of Agriculture, rather small and very excited. 'Do you do lots of these - things about religion?' he asks with a chuckle, and when I say no, I'd like things put simply, please, he says, 'Right] I shall be Un-confusing,' and chuckles again.
And then he says that his decision isn't about women: 'I am agnostic about whether women can be priests.' So what was all that quarrelling in the synod about? Oh, that was about women, but it shouldn't have been; that's why he's left. This is Un-confusing?
To be in the Church of England, according to Mr Gummer, you have to believe in three creeds and something he calls the orders of the Church, another name for the apostolic succession: 'Apostles made bishops who made bishops who made bishops - there is an unbroken chain of authority. Rather like a diplomat who has his authority from the Queen, bishops have their authority from other bishops.'
Couldn't one of these bishops just make a woman a bishop? 'No, no, no, I haven't said anything about that yet,' he retorts, swatting away this question and going back to Church history. 'What the Church of England said when it emerged from the Reformation was that, in essentials, it had not changed; it had just removed those things that had got stuck on, in medieval times. It was not a protestant church, but a reformed church.'
All this stuff about just removing the stuck-on bits, still really being catholic, is personally important to Mr Gummer. His father was a Nonconformist minister who moved into the Church of England, gave his three sons the same middle name (Selwyn, his own name, which John, alone, uses when he is trying for a bit of gravitas), and who was so good at sermons he used to sell them to other vicars to pay for the boys' education.
'I was brought up as an evangelical,' Mr Gummer says. 'Church services were enlivened by the sermon. You never went to sleep during the sermon; it was enormously exciting and invigorating.' This sounds implausible, and indeed before too long he decided that fewer sermons and more spirituality were in order. The breadth of the Church of England allowed him to move right over into Catholicism, without having to change churches. Until, perhaps, now.
All this does not, however, explain his problem with women priests. The nearest he can get to this is to say: 'It's very central to one's belief that you look for the reunion of Christendom.' So the only reason not to have women priests is because the Roman and Orthodox Churches might not like them? 'I don't know of any reason why women shouldn't be priests,' he answers, evidently back in Un-Confusing mode - but then rather spoils this by adding, 'except that they never have been, and Jesus chose not to have any as his apostles.'
He has to get to another meeting, then dash off to the Caribbean for the weekend - 'one flies in, chases round, sees a lot of people, it's not very nice at all' - but he is having such a good time talking about religion that he suggests I come along in the car. I sit squashed by old trays and cardboard boxes - 'stuff we brought down from the country for a charity thing' - while he makes vehement points on the evils of divorce. 'God created only two types of society, the family and the Church,' he says fiercely. 'Divorce is always damaging, and schism is a destructive force and can never be put right.'
I ask if one reason he doesn't like the idea of the ordination of women is that it's tainted by association with radical feminists? 'I think that is a bad way of saying something almost right,' he nearly agrees; and after a quick detour to assert that God is definitely our Father, not Mother, launches into cheerful spleen against 'the sort of feminist who seeks to replace the domination of men by that of women, enact the sin the other way round. The sort of writer who hates men clearly is sinful'.
The word 'sin' trips lightly off Mr Gummer's tongue. He seems untouched by modern notions of moral relativism that have bothered some churchmen. But then he likes a bit of clarity; he always liked that about the Church of England, that he could be sure about the creeds and the orders; there was a point at which you knew you were right, and you could shut everyone up by pointing this out. 'As we know in all other parts of life, where you really go wrong is if you start off having no security at all, and the whole thing becomes a totally wishy-washy mishmash,' he says.
He loathes liberal churchman ('the Bishop of Durham is such a Sixties person') and is less than fond of liberal newspapers. 'If you hate the sin, you are much more likely to love the sinner; if you have a woolly view about the sin, you are much more likely to get kicks out of kicking the sinner. That's what's bad about that woolly liberalism.' So he is quite unequivocal about it: divorce is always bad, sexual relationships (including homosexual ones) outside marriage are wrong; abortion is 'the single most expressive statement about the inhumanity of the 20th century'.
He is 'not at all fundamentalist' about the Bible, though he has 'no difficulty with the miracles. If you believe in the resurrection, the miracles aren't difficult. And if he's not risen from the dead, what the blazes am I doing talking about this at all? I mean, the whole thing would be a load of old rubbish - either he did or he didn't'
Heaven - about which he is vague - appears to be open even to those who don't believe, although he recommends The Towers Of Trebizond by Rose Macaulay, in which a priest 'tells a woman who announces that she will return to God eventually that it will be 'all right to give God the fag-end of your life: he'll take that because he's a loving God. But think of all the fun you're missing now]' ' That, he says, is exactly how he feels about it. And grinning impishly, he gets out of his ministerial car and skips up the steps to his next meeting.