"Now this madness of war is once more spreading through the world, and our brave country must again prepare itself to survive against great odds.
"I have never forgotten the sorrow and the pride I felt as my sister and I huddled around the nursery wireless set listening to my father's inspiring words on that fateful day in 1939. Not for a single moment did I imagine that this solemn and awful duty would one day fall to me."
The Queen never made that speech. Indeed, she may never have known about it. Written, as it was, fully 30 years ago as part of a preparatory exercise for a third world war that never came, it is really barely more than a footnote to history. It is not breaking news, after all, that the British government was more than a little nervous about the prospect of a nuclear conflict. We haven't learned anything substantive that we didn't already know.
And yet. When the speech was released last week as part of the latest National Archive declassification, most newspapers concluded that this figment was more interesting than a number of real events, from government plans to crush the trade unions to Margaret Thatcher's rejection of William Hague as a special adviser in the Treasury when he was 21. Why do we pay such rapt attention to a world that never was?
"Fate has ordained that the men who went to the Moon to explore in peace will stay on the Moon to rest in peace. These brave men, Neil Armstrong and Edwin Aldrin, know that there is no hope for their recovery. But they also know that there is hope for mankind in their sacrifice.
"In ancient days, men looked at the stars and saw their heroes in the constellations. In modern times, we do much the same, but our heroes are epic men of flesh and blood."
There is, in general, something dissatisfying about counterfactual history. It's too flimsy; it has no purchase on reality. No one can say meaningfully that world war would have been averted if Hitler had got into art school, or that Tim Henman would have won Wimbledon if Pete Sampras hadn't been around. Once you have taken more than a single step away from what really happened, the variables make all speculation pointless.
But the extraordinary words written by Richard Nixon's speechwriter William Safire above and baldly entitled "In Event of Moon Disaster", are a bit different. In this speech, as in the Queen's, the imaginary hardens into something tangible, something that was so nearly the case that it has left its shadow in reality. And so to read them is to feel the thrill of the uncanny, as if you have just received a postcard from an adjacent universe.
The two speeches have something else in common: they both imagine the worst, and leave us relieved that it didn't come about. When it comes to truly world-changing events, we don't do a lot of counterfactualising the other way round, maybe because we're so deeply programmed to interpret things as having gone for the best. There is no surviving text for a speech in which Harry Truman explains why the US didn't use the atomic bomb, or one in which Tony Blair explains why another UN resolution would be a prerequisite for invading Iraq. Perhaps they were written, but once the alternative course of action had transpired, it's only natural that their authors would be at pains to make their choices seem inevitable. How much more pleasant it is to creep to the edge of the precipice, and then draw gratefully back, than to peer up from the ravine below and know that you are stuck where you are.
"Our landings in the Cherbourg-Havre area have failed to gain a satisfactory foothold and I have withdrawn the troops. My decision to attack at this time and place was based on the best information available. The troops, the air and the Navy did all that bravery and devotion to duty could do. If any blame or fault attaches to the attempt, it is mine alone."
That's how General Eisenhower planned to break the news that D-Day was a disaster, that no second front had been created, and that Germany had retained control of Western Europe. Thank God he never had to do it.
Such artefacts are a powerful warning never to get too comfortable. They show us how perilously close this world is to not existing as we know it, how radically it can change, and how suddenly. Victory did not seem inevitable to Eisenhower. Perhaps there's even a little superstition in jotting down those words before the attack, a sense that the worst becomes more likely if you don't prepare for it.
That's the only explanation I can think of for one of the most curious relics of the Cold War: the tradition whereby each incoming British prime minister writes letters to the commanders of our ballistic missile submarines providing instructions for what to do if the country is wiped out by nuclear attack. The "letter of last resort" – not an ungiven speech, exactly, but a communication from an alternative reality just the same – is kept in a safe which sits inside another safe in the submarine's control room. It is the perfect expression of the lunacy of Mutually Assured Destruction, a doctrine that might require the deaths of countless civilians even after their annihilation can do us no good. And yet there the letters are, karmic insurance against a world so awful that they are destroyed, unread, when the prime minister leaves office, their secret so chilling that it can never be shared.
You can be sure that all over the planet, there are reluctantly superstitious political advisers carrying laptops that bear drafts of speeches written in a similar spirit. Collectively, they might be entitled "In Case of Emergency". This is an unsettling thought, a bit like the idea that newspapers have large files of obituaries for people who aren't yet dead. Does David Cameron have a speech prepared in case of a terrorist attack on London? Does Joe Biden know what he's going to say if Barack Obama is assassinated?
It must be an awful duty to write that sort of thing – to put in so much work on a project that you hope will be redundant, and to imagine your way into a catastrophe. To do so seems both solemn and obscene. When you read these speeches, part of their creepy power comes from the detail with which they are written: far more disconcerting than the Queen's boilerplate line about "the madness of war" is the passage later on in which the safety of her "beloved son Andrew" is called into doubt. In the document carrying Safire's speech for Nixon, likewise, darker even than the general idea of men hopelessly stuck on the Moon is the advice that the president should, before addressing the nation, "telephone each of the widows-to-be". For such scenarios to be presented, someone had to imagine the smallest particulars of what it would be like if they came to pass.
Of course, there are much more mundane situations that are deemed worthy of contingency planning. Since our leaders are an egotistical bunch, these are generally bound up in their own success or failure. Most of the time, the sensible politician will have these obliterated the second things go the other way. But sometimes circumstances dictate that they survive.
"Only four Labour leaders have ever been elected prime minister. Out of 14. Reflect on that. Many good men … lots of hard work … but only four have led us to victory.
"This leadership election, the new members, the new councillors, shows something is stirring. Something inspiring. We are not waiting to lose three times before we get our act together."
If you were looking for evidence that all was not well between the brothers Miliband after Ed's victory in the Labour leadership election, you could find it in the leak of that text: the speech David would have given had he prevailed. It's stuffed with lines that seem desperately ironic now to those Labour supporters who see the selection of their current leader as an act of political suicide akin to the Conservatives' choice of William Hague in 1997. Fairly or not, the existence of the speech makes David Miliband seem horribly presumptuous. Someone in his camp had to have had a pretty deep-seated objection to his brother to want to leak it.
Even though the motives for its existence and its revelation are so much less powerful than World War III or extraterrestrial disaster, the seductions of reading it are hardly different. The draw of these insights, it turns out, is not strictly correlated to the gravity of the circumstances that they imagine. Reading the Miliband speech, I found myself thinking of Mo Farah's recent challenge to Usain Bolt for a race over 600m. It isn't that anyone thinks the 600m the supreme test of an athlete's capacity, or seriously imagines that the contest would tell us anything definitive about either man. It's about novelty: the chance to imagine ourselves into a different world, without having to contend with the consequences.
"And I said to my husband Todd that it's not a step down when he's no longer Alaska's 'First Dude'. He will now be the first guy ever to become the 'Second Dude'."
For many people, those sentences will hardly be less alarming than those written for the Queen: they are extracted from the speech that Sarah Palin was determined to give if John McCain had beaten Barack Obama to the presidency. From them we can extrapolate the amusements of the meetings she might have held with foreign dignitaries without having to face up to the prospect of her having a plausible route to the nuclear football.
Another parallel presents itself. In the endlessly complex world of comic books, where superheroes' stories must take into account decades of overlapping and frequently contradictory history, and where every option must always be left open for the next plotline, really dramatic twists are difficult to engineer. If Lois Lane learns Superman's identity, she learns it for all time. The methods used to surmount this obstacle to compelling narrative are too various to describe here, but the simplest among them is a charming device pioneered by the writers at DC Comics in the 1940s: the "imaginary story", in which anything can happen without consequence in the "real" universe. Freed from their resistance to closure, the comics' creators came up with ideas as compelling as anything they ever wrote.
So it is with the speech not given, the calamity without consequence. To the Queen's speech, and to Nixon's, and certainly to Sarah Palin's, we might append the same line that closed one particularly grisly comic book, in which Lex Luthor lured Superman to a horrible death:
"Well, let's not feel too badly! After all, this was only an imaginary story … and the chances are a million to one that it will never happen!"