Prince Charles and Camilla: the timeless imperial grandees.

Prince Charles and the Duchess of Cornwall are given a traditional Maasi greeting during a visit to Tanzania. Photograph: Chris Jackson/Getty Images

Let's get away from it all. While Europe totters and the world economy lurches and stammers, Prince Charles and the Duchess of Cornwall seem in this picture to escape not just into Africa, but into the past. The photograph shows them receiving a traditional Maasai greeting in Tanzania this week but it could just as well have been taken in the same place 80 years ago when this former German colony was ruled by Britain under a League of Nations mandate. In their white clothes – which have the bizarre effect of contrasting them all the more self-consciously with the Africans they are among – they look like timeless imperial grandees, an effect enhanced by the Duchess's parasol. Yet the dark glasses and tie that Prince Charles wears also make me think of Graham Greene characters adrift in the heat.

This is no time to bash the royals. What would be the point? They didn't cause the crises of our day. And anyway, when it comes to the royal family, there is no get-out clause that allows us to say their trips abroad are Not In My Name. The royal wedding this spring proved that monarchy is as popular and enduring in Britain as it was in the days when this might have been a sepia print, the faces frozen for a lengthy exposure, with Prince Charles placing his foot on a newly killed lion. This is the image that Britain exports. We choose to be represented abroad by a royal family. Let's look at ourselves, for once, as others see us. What does this photograph's vision of a timewarped monarchy tell us about ourselves?

The peculiarities of the British have never been more urgent to understand: this picture reveals national traits that have become very relevant as the euro crisis unfolds. The euro may or may not survive but the fact is that we didn't join it. What kept Britain out? Was it the Tory Eurosceptics, Gordon Brown – or a spiritual insularity that is far older and more innate? This image says it all. We never were going to abandon sterling for two reasons that precede all others. We stayed out because we have a monarchy, and because we once had an empire.

Britain's crown is not just a piece of archaic decoration. It is archaic – how many other nations today might send an hereditary heir to a throne, who can claim a thousand-year-old right of succession on an official visit to Tanzania? – but it is not decoration. It has defined first English, then British, identity in a way that marks us out. Behind the desire of Germany or France to belong to a strong European union with a single currency lies a bloody history of war and revolution. From the wars of Louis XIV to the wars of Napoleon, from the French Revolution to the Franco-Prussian war, the path to modernity on the European continent was violent and contested. Long before the horrors of the 20th century, the fields of Europe were already deeply stained. Meanwhile, that strange island, Britain, saw mercifully few struggles on its soil after the restoration of the monarchy in 1660.

A liberal monarchy, gradually relinquishing most of its powers to ministers in parliament, evolved with a seeming inevitability in 18th and 19th century Britain. While heads of state came and went elsewhere, as change demanded revolution, in Britain huge leaps were taken towards democracy, including Disraeli's 1867 Reform Act, without once questioning the prestige of the crown. Since Queen Victoria, the monarch has symbolised British parliamentary democracy. This is still a deep constituent of our national nature. Why were we never going to give up the pound? Because it has the Queen's head on it. Even Leonardo da Vinci would never have been accepted as a substitute.

The second essential British attribute this photograph captures is that we created, ruled, and abandoned the biggest empire in the history of the world. History is not linear. Historical realities do not disappear like yesterday's headlines. The British Empire still exists. It still shapes the present, from the multiethnic character of modern British life to the arrogance that makes so many Britons sceptical of every aspect of the European Union. The Atlantic trade routes and naval supremacy that made us a world power in our own right are long gone. It is their memory that persists, and makes Britain suspicious of European attempts to overcome the prison of national sovereignty. In some dark corner of our imaginations, we are all Prince Charles, in sunglasses in Africa, dreaming of a time when we had our own economic union, with the Bank of England in charge, ruled by us, just as Germany may now have to rule the eurozone.

It would be tempting to turn the argument in a "leftwing" direction at this point, and to say that, just as Charles and Camilla seem surreally irrelevant in this photograph, Britain's delusions of uniqueness have made it irrelevant and weak in the modern world. Our coalition government frets uselessly on the sidelines of a grandiose crisis. Its entire economic policy is dwarfed by events it cannot control – which may at least give it an excuse. Meanwhile the navy of yore has been virtually abolished. Little England looks inward, watching Downton Abbey just as Charles re-enacts colonial nostalgia in this picture.

• But that is too easy. This photograph evokes the archaic nature of British identity. Now, is that archaism such a bad thing? It does seem that many critics of the European project, from whatever political position they spoke, have been proved right. The innate insular quaintness that makes us send a prince to Africa also made us suspicious of the abstract glassy edifice of the EU and above all its currency. Where does that leave Britain now? On the sidelines? Is that such a bad place to be?Yes, our economy will be sucked into any European disaster. But as the stakes get higher, it is deeply disturbing to see the same modernists who insisted on Europe as the saviour of democracy call for a "political clarity" in Greece and Italy that apparently now overrules democracy. This isn't just about the wealth of nations. And the British, once again, find themselves an island whose government and political culture are set apart, archaically royal, archaically democratic.