The Pope's visit to Britain this week has already aroused much excitement - much of it unwelcome. He can look forward to adverts on the sides of buses shouting "Pope Benedict - Ordain Women Now!". [2] There will be vigorous opposition from the Protest the Pope [3] movement, a broad coalition whose supporters include Southall Black Sisters, Peter Tatchell's Outrage!, the Council of Ex-Muslims and, thundering down from their Palmers Green fastness, the North London Humanists. And he will also have to avoid being arrested [4] by Richard Dawkins and Christopher Hitchens, who feel His Holiness ought to be tried for "crimes against humanity".

With all this goodwill towards the Vatican in the air, this may not seem the most auspicious moment for a leading Catholic thinker to declare that what England really needs to do right now is to "uninvent the Reformation". But that's exactly what Professor Nicholas Boyle, President of Magdalene College, Cambridge, authority on European thought and theology and acclaimed biographer of Goethe, says is required.

"In the moment of Henry's breach with Rome the fracturing of Christendom began," writes Boyle in his most recent book, 2014: How To Survive the Next World Crisis. [5]"How might we begin to envisage a new Christendom of which England might be a member as it once was of old?"

The Church of England could be forgiven for being a little alarmed at such talk. Following the Pope's announcement last year [6] that he is creating "a canonical structure that provides for... corporate reunion" to hasten errant Anglicans back to the bosom of Holy Mother Church, this may sound like another attempt to reclaim "Mary's Dowry" for Rome. Even the late Cardinal Hume [7] once let slip that he hoped for the "big moment of grace...the conversion of England for which we have prayed all these years."

Boyle certainly doesn't sound as though he'd be against that. "The Catholic church has a hotline to areas of society that politicians don't," says this energetic 64-year-old don, commended as "a critic of vivacious perspicacity" by George Steiner, when we meet for coffee at the British Academy in Carlton House Terrace. "It is concerned for the poor, the unemployed and the disadvantaged, and has a personal knowledge of them that even the most assiduous MPs don't have. If they do, you'll often find they're Catholics."

Mass conversion, however, is not quite his point. His thesis is that the Reformation is one of the causes of "that uncertainty about the national identity which continues down to our own day as the question 'are we English? Or British?'" In the sixteenth century, other European states (at least to begin with) remained united in Roman Christendom - "units within a larger structure, like colleges within a university," he says. Boyle's argument is that then, at the very point that an England newly separated from Rome began to think of itself as a modern nation, it was already confusing that sense of nationhood with the empire it was forging. Anglicanism and imperialism marched onwards, inextricably linked.

"That English nation was a creation of the British empire, like the English church it came into being in the 16th century." (Orwell's England, the one in which "the suet puddings and red pillar boxes have entered into your soul", was a late, but misleading, elegy to this.) Both, says Boyle, are now "obsolete"; and that presents challenges for both, as well. "England's protestant status was so bound up to empire, that when empire isn't there we have to think again."

Hmmm. Do we really? Yes, he says. "I think the UK will never know what it ought to do in Europe, with the United States and in the wider world, until it has rethought its history since the sixteenth century. It's no good saying you can't change the Act of Settlement," which provided in 1701, and continues to provide till this day, for the Protestant succession to the throne. "Everything that the act represents has changed. The empire has gone. The world around us has changed, and we haven't noticed that we've changed, too. Many of the unsatisfactory features of how Britain behaves in Europe, the hostility of campaigning atheists to the Pope's visit - much of this derives from an uncertainty about who we are."

So if we go back to that time, where does that leave England? "In fifteenth century Christendom it was one player, not the biggest, not the smallest either, in a multiplicity that was both religious, cultural and national, yet linked together by a common identity." The nation then was "not some aboriginal unit that comes into contact with other entities. The idea of the autonomy and sovereignty of a self-determining people doesn't go back much further than Woodrow Wilson." Supranational institutions like the League of Nations and the UN, says Boyle, "are bodies that unite only what they have previously divided. These apparently international bodies are a device for persuading us that originally we were all separate. This is one of the things the English have to learn."

Let's see: England sharing sovereignty and identity, uninventing the Reformation, being just one player in a modern Christendom. That couldn't be the European Union, could it? And if so, doesn't that confirm the suspicions of those who maintain that right from the signing of the Treaty of Rome (an unfortunate title in this context), the whole European project has been a Popish plot? Boyle laughs. "Well, it one sense it was. The founders were Catholic social thinkers. Schumann, Adenauer: these were people who did think of Europe as a social democratic reissue of Christendom. A lot of that continues. That's why it was totally absurd that the French were so against mentioning Christianity in the abortive EU constitution. That seems to me to be a denial of the facts."

None of this may strike Anglicans as terribly tempting. Bad luck to them, says Boyle. Their leaders have "been keeping alive a ghost of the church of empire." What does the future hold for them? "As far as the Church of England is concerned, it has a very good prospect as the Church of [only] England, ha, ha." Uninventing the Reformation might quite suit Prince Charles, I suggest, with his enthusiasm for being Defender of Faith rather than Defender of the Faith. "That is an abstraction," says Boyle. "From Hegel's point of view you can't be a defender of faith in general, it must be one faith in particular. But I don't expect the Prince of Wales to conduct himself according to the phenomenology of mind."

Ultimately, what Boyle is urging is an end to the idea of English exceptionalism and a reversion to a pre-Reformation universalism. "That's what Catholic means." He quotes the Gospel of St Matthew: "'Go ye, therefore, and teach all nations.' It's one of Christianity's foundational texts."

What would this vision mean, in practice? Boyle closes his new book with a summation. "That world of mercenaries and wandering scholars, when French was still written in England and Latin was spoken everywhere, can provide us with an example of how it is possible to live, and think of yourself, both as originating in a particular place or culture and as a member of a universal order." This new Europe, he writes, "will be a house with many mansions, most of which will not be recognisable to those who dwell in the nations of the past, but it will seem like home to those whose synapses can recall the still older Christendom."

A dream? Or a nightmare for Protestant Eurosceptics? Maybe. But as an alternative to a continent whose underlying unity is currently based, as Boyle asserts, on "Microsoft or global banking", perhaps not a bad one. I bet the Pope thinks so.