Saul Steinberg's 1976 New Yorker magazine cover of the world as viewed from New York City still adorns many walls in many homes in many countries. With the Manhattan streets drawn in close detail, the Hudson river in the middle distance and China on the far horizon, Steinberg's illustration brilliantly captures Big Apple narcissism. It deserves its much-imitated iconic status.

But how would a similar map of the world refracted through the mindset of London's metropolitan elite look in 2010? The City in the foreground, obviously. Perhaps Kensington eliding into the Cotswolds or the Welsh Marches in the near middle-distance. A strip of ocean with America looming large behind it. And, er, that's it.

There would be no place for Scotland or Ireland in this map. No surprise there, perhaps. More strikingly – and more surprisingly if compared with the kind of mental map that might have been drawn 20 years ago – there would be no place for continental Europe either. Not France, not Italy even. Certainly not Germany or Scandinavia. As for Russia, forget it. All out of mind. All out of sight.

It is hard to recall a time when the national, not just the London, mind was less informed about or engaged with Europe than it is today. Europe may still be this country's major export market. Millions may still take holidays there. Our football teams may still battle for the glamour of being "in Europe". In the larger sense, though, being in Europe has never impinged less.

This is not primarily a question of the rise and fall or marginalisation of the European Union. Clearly the union's diminished role helps to make Europe a harder sell. If the EU were more dynamic and effective – if it got its act together on common energy policy or with a shared global strategy for European universities, or even, however improbably, on defence or economic policy – then the current sense of Eurolassitude might be lessened.

But the national mental disengagement with Europe is not primarily political. It has grown independently of any events in Brussels. What we are experiencing is, above all, a cultural change. And it is being driven by our use of – and the commercial priorities of – all forms of new media.

The online information age, which should, in theory, have been expected to facilitate greater mental and cultural pluralism and thus, among other things, greater familiarity with European languages and cultures, has, in practice, had the reverse effect. The power of the English language, at once our global gift and our great curse, discourages us from engaging with those – the 93% of the world who speak some other first language than English and the 75% who have no English of any kind – outside the all-conquering online Anglosphere.

In the 20th century, political, cultural and intellectual Europe was a reality. Sometimes a threat, often an opportunity, but always a presence. That's not true now. In the 21st century, to a degree we seem slow to recognise, let alone think about, our minds have never been more narrowly oriented towards the English-speaking world, above all the US. For us, global vision is increasingly also tunnel vision.

This struck me most recently over the death in a plane crash last week of the former US senator Ted Stevens, of Alaska. Even a decade ago, the death of a former US senator, and especially one from a place like Alaska, which, as the cold and exhausted crow flies, is the best part of 5,000 miles from where most of us are sitting, would barely have registered in the British media. These days, though, anything that is a big story in the US media seamlessly becomes a big story in the wider Anglosphere too. The result is that most people in this country can name more Alaskan politicians than they can name Dutch ones.

And now it is not just America. Tomorrow there is a general election in Australia. An interesting event, of course. One of the few centre-left governments of the modern era, and now with a woman leader, battling to withstand a rightwing challenge led by a climate change sceptic. But it is getting far more coverage in Britain than any Australian election in my memory. Why? Not because it is more important, but simply because they speak English.

Don't get this wrong. It is good that people in Britain are being informed about the politics of Alaska and are getting engaged in the politics of Queensland. It's just that I want them to be interested in the politics of the Pas de Calais and to be informed about those of Lower Saxony, too. But these bits are simply not happening. Mental fog in the Channel; continent cut off.

This autumn we will be bombarded with news about the US midterm elections. Fair enough. These are significant elections in the world's most powerful country. But if we are to be intelligent and rounded beings we also need to be well informed about and engaged with elections in places much nearer to home, and especially those that arguably have more to tell us about the temper of the times in our part of the world – like those in Sweden next month – above all.

But that is not going to happen as long as we are voluntarily imprisoned in the Anglosphere. Yesterday, once again, the latest generation got fewer A-levels in French, German, Russian and Spanish than the generation before. Next week, there will be fewer GCSEs in modern languages too. The trend is inexorable. We are cutting ourselves off from the world. Another New Yorker cartoon, this time by Robert Mankoff, comes irresistibly to mind. A woman is talking to a man at a cocktail party. She asks: "One question: if this is the information age, how come nobody knows anything?"

The answer is simple. They are speaking to us from outside the Anglosphere but we no longer understand them. The internet – on which we all spend so much of our time, as Ofcom reported this week – is in danger of becoming Britain's staycation of the mind.