The break-up of the UK would represent a sad coda for the Queen

Yet beyond the familiar there always lurks the dark matter of politics, which conceals the unanticipated and the surprising until they burst through into the arc-lit hustings. Already the one shared expectation of the 2019 election, from the very moment the House of Commons fixed 12 December as polling day, is that in party terms it will be the most volatile and fluid in anybody’s memory.

Prediction, therefore, is even more perilous than usual. But it is fair to say that in the long sweep of British political history, this will be a truly heavily freighted election in terms of its enduring significance. How the European question plays out, not just in what could be the United Kingdom’s withdrawal phase but also through the negotiation of the future trade relationship with the EU 27 during the 2019-24 Parliament, could not be more fundamental.

But 12 December 2019 might also represent another historical way station of huge import. For it could be the last time MPs from Scotland are returned to the Westminster Parliament. The Scottish question was vividly put in The Guardian last month by Neal Ascherson when he claimed that “Brexit has delivered the United Kingdom to the hospice of history”. I hope it hasn’t – but I fear it has.

If that turns out to be true and Scotland separates, it would represent a number of things. Unlike our withdrawal from the EU, it would probably be irreversible. It would change the way we imagine both Scotland and the “remainder of the UK”, which would be greatly the poorer given that the people of Scotland, out of all proportion to their numbers, have brought such riches to the shared UK table in learning, science, technology, the military arts and the crafts of government and diplomacy and much more since the Union was created in 1707.

The break-up of the UK would also represent a sad coda in the twilight years of her reign for the Queen, who cherishes every particle of her kingdom as she made plain in her address to Parliament in Westminster Hall during her Silver Jubilee year, when she said: “I cannot forget that I was crowned Queen of the United Kingdom of Great Britain and Northern Ireland. Perhaps this Jubilee is a time to remind ourselves of the benefits which Union has conferred, at home and in our international dealings, on the inhabitants of all parts of this United Kingdom.”

In political terms, a Scottish separation would almost certainly change the nature of the party structure in England and Wales – the argument being that the centre-Left would have to remake itself if it were to be a serious and regular contender for power at Westminster. This might also require some form of proportional representation for elections to the House of Commons to provide the necessary lubricant for a new political system.

There is a possibility that in the backwash from the 12 December election such a party realignment might be under way before Scotland votes again on independence, if our political ecology is truly morphing into a pattern in which the old cartography no longer fits. If that proves to be so, we could be in for a spate of general elections, though three in five years is exhausting enough.

May I finish with a personal footnote? As a political historian I am supposed to resist the charms of golden-ageism. But I cannot help remembering that in the first general election in which I took a close interest – 1959 – the political leadership on offer was a choice between Harold Macmillan for the Conservatives, Hugh Gaitskell for Labour and Jo Grimond for the Liberals; broader gauge figures all three. Those were the days …

Peter Hennessy is Attlee Professor of Contemporary British History at Queen Mary University of London and an independent crossbench peer. His book Winds of Change: Britain in the Early Sixties is published by Allen Lane, £30 (Tablet bookshop price £27).