The war in North Africa had been going backwards and forwards along the coast for two years, and it looked, on a map, like a piece of elastic.
One side would advance five hundred miles, outrun its own fuel and food, stop, and be pushed five hundred miles back by an enemy who then did exactly the same thing. Tobruk changed hands repeatedly. Nobody could hold what they took.
The reason was the desert itself. South of the coast road the ground is open for hundreds of miles, so any position could be gone around. There were no flanks anywhere, which meant there was no line anywhere.
Except in one place. At a railway halt called El Alamein, about sixty miles west of Alexandria, the Mediterranean is on one side and an enormous impassable depression of soft sand, the Qattara Depression, is on the other.
The gap between them is roughly forty miles wide, and it is the only place in a thousand miles of coast where an army cannot be outflanked.
Behind El Alamein was Alexandria, and behind Alexandria was the Suez Canal.
Beyond that were the oilfields of the Middle East, and a land route toward the Soviet Union's southern flank, and the shortest sea link between Britain and India.
In the summer of nineteen forty two the German and Italian armies under Rommel had come within sixty miles of Alexandria, and in Cairo the British embassy burned so many documents that the ash fell over the city, and people still call it Ash Wednesday.
Rommel had a nickname by then, the Desert Fox, and it had been earned. He was very good at moving fast and at persuading an opponent that he was somewhere he was not. He also had a supply line that ran from Italy across a sea the Royal Navy and the Royal Air Force were operating in, and by the autumn of nineteen forty two roughly a third of everything sent to him was going to the bottom of the Mediterranean.
It was stopped, in July, in a first battle at the same position. Then both sides dug in and spent three months getting ready.
In August, Churchill flew to Cairo and changed the command, in a rather brutal sequence: his first choice was killed when his aircraft was shot down on the way to take up the post, and the job went instead to Bernard Montgomery.
Montgomery was, by common consent, difficult, boastful, tactless, and extremely good at exactly this problem.
He did three things immediately. He announced publicly that there would be no further retreat and had the contingency plans for withdrawal destroyed. He went round and talked to the troops in person, constantly, in a way British generals had not much done, wearing a peculiar hat covered in regimental badges that everybody found faintly ridiculous and remembered forever.
And he refused, flatly and repeatedly, to attack until he was ready, no matter who asked. Churchill asked, more than once, with increasing irritation. Montgomery said no.
He wanted overwhelming material superiority and he waited until he had it: roughly two to one in men, and better than two to one in tanks, including three hundred new American Sherman tanks that had been shipped round the Cape.
The Eighth Army at El Alamein was one of the most mixed forces ever assembled under one command, and this is worth listing properly.
There were British divisions, and Australians, and New Zealanders, and South Africans, and Indians. There was a Free French brigade, and a Greek brigade, and a Polish brigade that had reached the desert by way of Syria and Palestine.
The Indian divisions in particular are routinely left out of the popular story and were central to it. The Indian Army in this war was the largest volunteer force in history, around two and a half million men, and its divisions did a great deal of the hardest fighting in North Africa and later in Italy and Burma.
The nickname Desert Rats belonged properly to one formation, the Seventh Armoured Division, whose emblem was a jerboa, a small desert rodent that jumps. It spread until it was applied to the whole army, which annoyed the Seventh Armoured considerably.
Before the battle, the Eighth Army ran a deception operation with a very literal name: Operation Bertram.
The aim was to convince German reconnaissance that the attack would come in the south, and that whenever it came, it would not be soon.
In the north, where the attack would actually fall, a thousand guns and hundreds of tanks had to be hidden in flat open desert. So tanks were parked and covered with canvas frames that made them look, from the air, like supply lorries. Lorries in the south were covered with frames that made them look like tanks.
A dummy water pipeline was built toward the southern sector, slowly and visibly, with dummy pump houses and dummy storage tanks. The rate at which it was being built told any observer exactly when the southern attack could begin, and the date it implied was several weeks after the real attack was due.
Much of this was designed by a stage magician, Jasper Maskelyne, whose later accounts of his own war work are so exaggerated that historians treat them with great caution. The deception itself was real, was largely the work of a team of camouflage officers and artists, and it worked.
At twenty to ten on the night of the twenty-third of October, more than eight hundred guns opened fire together.
People in Alexandria, sixty miles away, felt it. It is generally reckoned the heaviest artillery barrage the British Army had fired since the previous war.
Then the infantry went forward into the minefields, because the whole position was fronted by belts of mines half a million strong, which the Germans called the Devil's Gardens. Engineers went ahead with detectors and bayonets to prod for mines, marking cleared lanes with tape and shaded lamps, under fire, to open corridors for the tanks behind.
It did not go to plan. It rarely does. The corridors were too narrow, the armour got jammed in them, and after a week the battle had become a grinding fight in which Montgomery was widely thought, back in London, to have stalled.
The Australian division in the north fought a series of attacks through that week that drew the German armour toward the coast, which is what made the second blow possible further south. It cost them heavily and it is the part of the battle Australians remember and most other people do not.
He regrouped, shifted the point of attack, and struck again on the second of November. By the fourth, the line broke, and the German and Italian forces began a retreat that did not stop for fifteen hundred miles.
Rommel had been in Germany on sick leave when it began and flew back on the second day. He had, by then, very little fuel, and an army that could not run away fast enough because much of it was Italian infantry with no transport at all.
This was the first clear British land victory over a German army in the entire war, after three years of defeats, and the effect at home was out of proportion to the size of the battle. Church bells were rung across Britain for the first time since nineteen forty, when they had been silenced to serve as an invasion warning.
Churchill said of it that it was not the end, and it was not even the beginning of the end, but it was perhaps the end of the beginning. He also said, more privately and more accurately, that before Alamein the Allies never had a victory and after it they never had a defeat.
Four days after the breakthrough, American and British forces landed at the other end of North Africa, in Morocco and Algeria. The German and Italian armies in Africa were now being squeezed from both directions and surrendered in Tunisia the following May.
Here is something to think about tonight. Montgomery refused to attack until he was ready, and was called slow and timid by people who wanted good news immediately. He was right, and being right cost him a lot of goodwill at the time. When is it worth being unpopular for a few weeks?