In April 1942, the Luftwaffe launched a series of night bombing raids against the historic cathedral cities of Exeter, Bath, Norwich, York and Canterbury. The targets had been picked out of the Baedeker Guide to Britain, not because they were militarily important or commanded crucial transport routes, but because they represented something vaguer but more profound.
The Nazis' aim was to smash Britain's moral and historical heritage – and, of course, they failed. More than 1,500 people were killed, but York Minister and Canterbury Cathedral still stood proud and unbowed amid the flames, symbolising the long centuries of England's past. Not even the might of the Nazi empire, it seemed, could break the thread of our national history.
What a tragic irony, then, that where Hitler's bombers failed, a generation of home-grown political meddlers and "progressive" educationalists have succeeded all too well. For to anyone with even a passing interest in the teaching, reading and writing of our national past, the Historical Association's massive new survey on history teaching in secondary schools reads like the report of some callous, devastating military barbarism.
Across the board, history teaching is in retreat. Seven out of ten teenagers say they enjoy the subject, yet barely three out of 10 study it to GCSE level. Among younger children, the hours set aside for history are being slashed to make way for supposedly vocational subjects. And almost unbelievably, 12-year-olds in half of Tony Blair's beloved academies study history for just one hour – one! – a week.
An entire generation, in other words, is leaving school ignorant of what their parents and grandparents once took for granted: the solid, reassuring knowledge of what we all once recognised as our national story.
Terrible as they are, the Historical Association's figures come as little surprise. A few years ago, when I was a lecturer at one of northern England's biggest redbrick universities, I quickly realised that it was a mistake to assume any prior knowledge of British history on the part of our 18-year-old students. Most had studied the Nazis and the American civil rights movement in great detail at A-level, but few had heard of, say, David Lloyd George or Stanley Baldwin, or could explain why Britain had won and lost a global empire.
They were bright and keen to learn, but had been betrayed by a system that fed them titbits of knowledge, and by a culture of continuous testing that left little time to appreciate the broad sweep of our national past. But by today's standards, they were lucky. For as the Historical Association points out, if the trend continues, history may well decline into virtual irrelevance as a school subject, overtaken by Media Studies and Beauty Therapy.
It is too easy to blame the students, who find themselves under intense pressure to get the best possible grades for their university applications – which inevitably means that they pick subjects that are seen as "easier" or that offer more "value". And it is too easy, I think, to blame their teachers.
Whenever I give sixth-form talks, whether in private or state schools, I am always struck by the sheer love of history shown by most teachers, whose attitudes often put academics themselves to shame. Only a few weeks ago, giving a lecture to a talented and engaging group of A-level students on the Isle of Man, I felt almost humbled by the enterprise and sheer commitment of their history teachers, a husband-and-wife team who might have been an advertisement for education as one of life's most enriching vocations.
But there is no doubt that something has gone badly wrong when seven out of 10 schoolchildren are no longer studying history at the age of 16, when two out of 10 think Britain was once occupied by the Spanish, and when some identify Sir Winston Churchill as the first man on the moon. And the blame lies at the very top, shared by politicians of both parties, who have been systematically cheating and betraying our children since the 1980s.
During the Thatcher years, it was meddling from the top that downgraded history from a compulsory to an optional subject at the age of 16 – which, because it was seen as "difficult", made it easy pickings for Mickey Mouse subjects such as Beauty Therapy. It was supposedly "progressive" interference, meanwhile, that did away with old-fashioned essay questions and replaced them with empathy exercises and multiple-choice quizzes that sacrificed any sense of intellectual depth or discipline.
And perhaps above all, it was in Westminster and Whitehall that officials designed our absurd Yo! Sushi approach to history, in which schools randomly pick unrelated historical topics like saucers from a conveyor belt, instead of studying our national story as a continuous narrative, which is how any sensible person sees it.
What makes this betrayal all the more depressing is that in society at large there is clearly such an eager appetite for historical narrative. Even now, 20 years after I was forced to do empathy exercises ("Imagine you are a housewife in Hamburg in 1932 …") as part of my history GCSE lessons, British readers devour more popular history than almost any other nation, helping to keep Andrew Roberts in silk pyjamas and Simon Schama in leather jackets.
With almost four million members happily forking out to visit its country houses, castles, factories and workhouses, the National Trust is the biggest membership organisation in the country. Even the latest Booker shortlist reflects our deep shared thirst for history, from A S Byatt's lovingly evoked Edwardian social landscape to Sarah Waters's haunting recreation of Attlee's Britain and Hilary Mantel's coruscating portraits of Thomas Cromwell and Henry VIII. And, of course, it was the readers of this very paper who contributed £25,000 to the reprint of H E Marshall's Our Island Story, the children's history of England first published in 1905 that still gives a more entertaining overall account of our national story than most modern textbooks, even if it is a bit dated.
Any sensible government, recognising the extent of the popular enthusiasm for history, would have intervened long ago to restore the subject as a central, compulsory element of the national curriculum. Instead, Labour have flapped and floundered, bleating about Britishness lessons and citizenship classes instead of doing the one thing guaranteed to inculcate a sense of community and identity: teaching children their national history.
One reason that America has proved so successful as a melting pot for immigrants, after all, is that its schools give their children a solid and reassuring sense of themselves as Americans, embedded in a shared national past which is studded with patriotic landmarks from the Declaration of Independence to the Gettysburg Address. And we have only to look across the Irish Sea, where schools in the Republic patiently trace their national story from Ireland's first Christian missionaries to its bloody struggle for independence, to see that teaching your national history from start to finish is hardly rocket science. Nor is it necessarily reactionary or old-fashioned or even conservative, as its critics suggest. It is simply common sense.
"The past is a foreign country," L P Hartley famously wrote at the beginning of his great novel The Go-Between. "They do things differently there." Exploring that vast and impossibly rich continent ought to be one of the most exciting intellectual adventures in any boy or girl's lifetime: a chance not just to tread the fields of Hastings or Bosworth, or to see Shakespeare and Milton at work, but to encounter an enormously, uproariously diverse range of characters, to make lifelong acquaintances, to draw lessons and parallels, to meet humanity in the raw.
In any sane and decent society, that journey ought to be the centrepiece of the education system, a long and thoughtful expedition, not a botched and half-hearted day-trip to which most children are no longer invited. And one day, I suspect, we will look back and judge that our Government's ignorance and neglect of that wonderful, dazzling, irresistible country was among the greatest of its failures and the most unforgivable of its many betrayals.
'White Heat: A History of Britain in the Swinging Sixties' by Dominic Sandbrook is published by Abacus, £12.99