“Overall, the proposed legislation is of shocking severity and I can’t see how it could be supported by any Anglican who is committed to what the Communion has said in recent decades,” says Dr Williams. “Apart from invoking the death penalty, it makes pastoral care impossible – it seeks to turn pastors into informers.” He adds that the Anglican Church in Uganda opposes the death penalty but, tellingly, he notes that its archbishop, Henry Orombi, who boycotted the Lambeth Conference last year, “has not taken a position on this bill”.

With Anglican friends like those in America and Uganda, one wonders whether Dr Williams really needs Pope Benedict XVI, whose surprise new Anglican Ordinariate in October offered a home in Rome for disaffected Anglo-Catholic traditionalists. Dr Williams declines to be drawn on whether, when he saw him in Rome recently, the Pope was regretful or sorry for effectively jumping him – “private conversation, I think” – but he does concede that the hastily convened press conference, at which he sat uncomfortably alongside the Roman Catholic Archbishop of Westminster, Vincent Nichols, was a big mistake.

“I think everyone on the platform was a bit uncomfortable ... I know the Congregation for the Doctrine of the Faith on the whole doesn’t go in for much consultation – we were just on the receiving end of that.”

Really? Isn’t there something rather acquisitive and invasive about this Pope, who wants us to know that there is one universal voice of authority and it speaks from Rome? Dr Williams suddenly opens up: “Nothing entirely new about that of course. At the end of John Paul II’s pontificate you have that discussion of how papal authority is meant to be understood, how it might be received by others. I think that’s treading water at the moment. I’d like to see that revived and that’s part of what I was nudging at in Rome.

“Second thing is that in British Catholicism there’s a kind of resurgent – no – recurrent cycle of the 'second spring’, in Cardinal Newman’s imagery, and in the wave of distinguished converts in the interwar years, Evelyn Waugh and so on. There was just a hint of it when Cardinal Hume uncharacteristically talked about the reconversion of England – and I think he regretted that actually. And a few people in the last round. It’s a pattern, the sense that the Reformation wounds are going to be healed in favour of Rome. And it just keeps coming back – I think this has been the occasion for another little bit of that. It’s bits of the repertoire.”

The languid manner in which he delivers this leaves no doubt that he’s not holding his breath for a Roman second spring either. I wonder whether the Pope has, unwittingly and ironically, provided the kind of “third province” that Anglo-Catholics were demanding because they can’t accept women bishops, lesbian or otherwise. The Revision Committee for women bishops, after all, dropped proposals for legal protection for them in the wake of the Pope’s initiative.

“I would guess that the papal announcement had some impact on the way some people thought and voted on the committee,” concedes Dr Williams. “But actually I don’t think it is a solution. A great many Anglo-Catholics have good reason for not being Roman Catholics. They don’t believe the Pope is infallible. And that’s why they’re still pressing for a solution in Anglican terms, rather than what many of them see as a theologically rather eccentric option on the Roman side.”

Significantly, he still wants formal protection in the Anglican Church for those who can’t accept women priests. I put it to him that ordained women believe that idea has been thrown out. “Well, we’ll see,” he responds. “We’re still halfway through our process.” But whatever the differences with Rome, Dr Williams was anxious to stress that a third round of ecumenical talks, the “Arcic” initiative, for next year was nailed down in Rome. He calls that a “small miracle”.

“I think reports of the death of Arcic have been much exaggerated,” says Dr Williams with a rare laugh. “There are a lot of Roman Catholics who want a chance to talk. They need an ecumenical forum to do that.”

This is the internal politics of the Church. What about the more dirty politics across the river from Lambeth? What would he like to see from politicians in the coming general election year? He responds that we “curiously have three party leaders, all of whom have a very strong moral sense of some spiritual flavour”. David Cameron may have conceded that the Church of England is in his DNA, but Gordon Brown is a son of the manse who is notoriously secretive about his faith or lack of it, and Nick Clegg has declared his atheism. “But he takes it seriously,” replies Dr Williams. “And with all of them I think if you can get them off the record or off the platform, these convictions will come through quite strongly.”

Is the problem “we don’t do God” spin doctors? “I think it’s important for politicians not to be too protected, to be able to establish their human credentials in front of a living audience.” So our leaders need to be more open about their faith? “I don’t think it would do any harm at all. Part of establishing their human credentials is saying 'This is where my motivation comes from?... I’m in politics because this is what I believe.’ And that includes religious conviction.

“The trouble with a lot of government initiatives about faith is that they assume it is a problem, it’s an eccentricity, it’s practised by oddities, foreigners and minorities. The effect is to de-normalise faith, to intensify the perception that faith is not part of our bloodstream.”

Between our Canterbury and Lambeth meetings, I attend a Christmas reception at Number 10. The Prime Minister tells us: “I don’t subscribe to the naked society. I don’t subscribe to the secular society.” Perhaps Dr Williams is catching a political second spring.

He seems to want to get stuck into some of those politics. Protecting the rural economy from rapacious supermarket chains is a case in point. And he wants the Church of England to step up to the plate in the rural communities that he has recently been visiting, encouraging the “unsung heroes” in his flock.

He proposes a “supermarkets ombudsman” and reckons the bishops in the House of Lords can and should play a role in establishing the post. “We need more care in holding together the environmental and conservation agenda with the food production agenda in some areas.”

It will be engaging to see what Lord Sainsbury, for one, makes of such proposals from the Lords Spiritual. But nothing will happen, will it, without political, as well as religious, conviction? “I think we’ve lost a sense of what we really understand by public virtue,” says Dr Williams quietly. “Character is something that has fallen off the radar for quite a lot of people.”

Would he like to hear our political leaders saying something similar from their public pulpits during this last Christmas before the election? The Archbishop of Canterbury is making no political predictions, but smiles: “I’d be very happy if they did, yes.”