And did those feet in ancient time walk upon England’s mountains green? No. And was the holy lamb of God on England’s pleasant pastures seen? No. And did the countenance divine shine forth upon our clouded hills? No. Yet I’m sure that we, the English, should adopt William Blake’s Jerusalem as our national anthem and sing it on all possible occasions.

There are two reasons for this, one serious and one seriously serious. The serious reason is that we can’t let the Scots, the Welsh and the French have all the best tunes. At rugby matches, the French sing the world’s best national anthem, while the Scots and the Welsh also have fantastic songs: the rousing Flower of Scotland, celebrating the Scots’ victory over the English as recently as 1314, and the magnificent Welsh Land of my Fathers, also celebrating resistance to the English enemy. Then we intone God Save the Queen, which is supposed to unite the English, Scots and Welsh. Anyone for warm beer and cricket? (Useless but enjoyable fact: God Save the Queen shares a tune not just with the American My Country ‘tis of Thee, but also with the anthem of that great tax haven Liechtenstein.)

The seriously serious reason is that there is now an England-shaped hole in British politics. At the moment, all the affective power of England and Englishness is being taken by the conservative, Eurosceptic, xenophobic end of the spectrum, all the way from the extremist English Defence League to mild middle England Brexitism.

Wherever the flag with a red cross on a white background flutters on St George’s day, 23 April, there as likely as not a vote for Brexit will follow on referendum day, 23 June. And the affective power is enormous. Britain and Britishness simply cannot compete when it comes to poetry and emotion. There’s some corner of a foreign field/ That is forever Britain? No, sorry, that doesn’t work.

This wasn’t so much of a problem when Englishness and Britishness were rolled up together, as in most of the rhetoric and song of the second world war. But now, when Scotland and to a lesser extent Wales have so much separated out, it cannot be ignored.

There are elections in Scotland and Wales on 5 May. I’m an addict of newspapers and current affairs programmes, but I have only the vaguest idea what the key issues are. Either this is not reported or I simply blend it out. They may not yet be separate countries but they are, to a growing degree, distinct polities.

We intone God Save the Queen – supposed to unite the English, Scots and Welsh. Anyone for warm beer and cricket?

In a splendid essay in the New Statesman, David Marquand tells us that the Welsh word for England means “the lost land” – lost to the Celts, that is, when the Anglo-Saxons drove them out. The strange thing is that England is also something of a lost land for the English. Again and again, people quote GK Chesterton’s poem about the “secret people” of England who “have not spoken yet”. Speaking on St George’s night in 1933, Winston Churchill referred to England as “a forgotten, almost a forbidden word”. Englishness was perhaps the first and certainly the most willing of the many national identities on these islands to be taken into the baggy imperial idea of Britishness, and it is the last and slowest to emerge from it.

Some people think this slowness is a good thing, because, they say, when it re-emerges it will inevitably be an ethnic, xenophobic nationalism: Nigel Farage with knobs on. It’s true there is such a tendency.

When Farage was heckled in Scotland, he fulminated against “anti-English” behaviour. When I went hunting online for a source for the Churchill quotation, I was taken to a speech by Enoch Powell. Britishness may historically be the imperial identity but, having been a duffel coat containing four home nations and many dependencies, its post-imperial incarnation is also quite baggy and undemanding: all you have to do to be British is to obey the law (most of the time), and know how to complain about the weather. Englishness can seem more ethnically exclusive.

Part of the appeal of the Brexiteers is a certain kind of John Bull English forthrightness. “Yet is there no man speaketh as we speak in the street?” ask Chesterton’s secret people, and the Brexiteers reply “we do”. Where they claim to speak for Britain, the bulldog whistle tells you they speak for England.

There is, however, nothing inevitable about this one-sided appropriation. The flag of St George will only blow to the right if English people who are liberal, open-minded and tolerant let it go by default. So we must defend England against the EDL. We all know that national identities are imagined and reinvented from a tissue of history and myth. As George Orwell says in his essay on the English people, “the belief that we resemble our ancestors – that Shakespeare, say, is more like a modern Englishman than a modern Frenchman or German – may be unreasonable, but by existing it influences conduct”.

It would be foolish to deny that there is plenty of material in English history and myth for a conservative nationalism. But there is also ample stuff for a liberal, progressive, open patriotism, from the 17th-century English revolution, through John Stuart Mill, all the way to the post-1945 Labour leader Clement Attlee’s commitment to build “a new Jerusalem” (as in the anthem) and Orwell, the Saint George of the English liberal left.

Of course I’ve gone back to Orwell’s essay The Lion and the Unicorn. England, he writes – he usually did write of England – must be true to herself, and “she is not being true to herself while the refugees who have sought our shores are penned up in concentration camps and company directors work out subtle schemes to dodge their Excess Profits Tax”. (Well may you mutter “plus ça change … ”)

And his great conclusion: “We must add to our heritage or lose it, we must grow greater or grow less, we must go forward or go backward. I believe in England, and I believe that we shall go forward.” Think of Orwell and put out more flags on St George’s day. England is coming back, one way or another, and it’s for us to make it a better way.