Last time, I was telling the story of how the three Polish whizz kid mathematicians, Marian Rejewski, Jery Rozycki and Henryk Zygalski, had told the British and the French, everything they had discovered about Enigma. Here they are:
That generous act enabled the British to begin decrypting German messages almost straight away, and, very soon, to start affecting the outcome of the war. In March-April 1941, Enigma revealed, for example, that Crete was going to be invaded from the air, using gliders and paratroopers. Everybody was ready for them and the German invasion force suffered heavy casualties, with as many as 4,000 men killed.
I also talked last time about how, in May 1941, the Royal Navy was told the whereabouts of all the supply ships that were servicing the Bismarck. They also ascertained on one particular occasion, that the Bismarck was headed to a harbour in France, rather than in Germany.
The stories all came from the book by John Jackson which relates the story of Enigma, the German encrypting machine used throughout the entire Second World War, the Germans always confident that their codes could never be cracked….
In July 1942, if the Royal Navy had been clever enough to believe the Enigma decrypt given to them, they would not have told the Arctic convoy PQ17 to scatter, an act which condemned 24 ships to a watery grave and 153 sailors to an early death. Arctic convoys were dreadful:
Temperatures were always unbelievably low, and the ships were attacked more or less constantly: 
There was very little air cover, and the one constant threat was the mighty battleship, the Tirpitz:
Even Enigma cannot overcome the arrogance of unintelligent senior officers. And what was the reason for the mix-up?
Well, the great men at the top end of the Royal Navy believed that the Tirpitz had left port to attack the convoy. But, unbelievable as it may seem, they were actually mistaken and the biggest naval disaster of the Second World War ensued.
In April 1944, General Guderian went on a tour of the various armoured units that the Germans had stationed in Normandy. This enabled the Allies to know exactly which Germans were where, and gave them…….
“a splendid insight into the distribution of the armour a month before the landing.”
Here is General Guderian. He was the author of the definitive book on tank warfare called “Panzer”. If only one of the senior English officers had read it before the Panzers rolled into France in 1940:
Further Enigma decrypts in 1944 revealed exactly the strength of the Germans in northern France, with six top quality divisions in France and Belgium, along with fourteen divisions of lesser quality. Worryingly, perhaps, the Cotentin Peninsula, to the west of the D-Day beaches, was being heavily reinforced, although it was music to Churchill’s ears to hear the large number of complaints from a large number of various German units that petrol and oil were again in very short supply. The Prime Minister was also extremely pleased to hear that, day by day, Hitler and his generals were beginning to believe more and more strongly that the Allies would land not in Normandy, but in the Pas de Calais.
Enigma decrypts also revealed that in, May 1944, the Luftwaffe had a thousand aircraft including 650 fighters, although Allied numbers were much, much, higher. Interestingly, given that the weather satellite had not yet been invented, the Allies were delighted that on D-Day, thanks to Enigma, they would be able to use what were probably far more accurate forecasts than anything they had themselves, namely the Germans’ own weather forecasts.
In June 1944, Enigma also managed to decipher encrypted messages between Peenemünde and Blizna, a testing ground for the V1 and V2. Before long, everybody at Bletchley Park was familiar with the name of Werner von Braun, soon to give up being a career war criminal and to move to a cushy well paid job in the United States.
Here’s a V2 rocket:
They were tested initially at Peenemünde and then at Blizna. Not a lot went on without the Enigma decrypts letting the RAF know something about it. Peenemünde was heavily damaged after a huge number of RAF bombers bombed every square foot of the site. They included 103 Squadron, starring my Dad. The RAF were particularly keen to blast and obliterate Peenemünde, because they’d all been told……
“Destroy the secret weapon site tonight, or you’ll all have to go back tomorrow evening.”
The main scientist in charge at Peenemünde was, of course Werner von Braun, not an SS war criminal who used slave labourers to build whatever he required but a helpful scientist who took Mankind to the Moon. Here he is, sharing one or two Slave Labourer jokes with his pals:
At the time, the people deciphering the Enigma messages were absolutely amazed at what the Germans were doing. They had never anticipated what were, after all, artillery shells, being propelled around a hundred miles to blow up either London or Antwerp. By late 1944, the so-called “Rocket Bradshaw” decrypts were providing everybody with the Germans’ timetable of all the V2 launches from the Hague area of the Netherlands, all of them targeted on London. The exact target was always Tower Bridge although they never got within a mile of it.
One final thought, which does not actually come from John Jackson’s book but from a TV programme I saw about the Final Solution. I hadn’t realised that there were still Enigma encrypts which had defied all attempts to decipher them. One of them was deciphered as recently as 2020. It was a careful record of how many Jews had been rounded up from the ghettoes in a score or more towns and cities in central and eastern Poland and had now been transported to Auschwitz-Birkenau and murdered. They were apparently using their strongest encryptions for that one.
The German Navy, the Kriegsmarine, had a very slightly different alphabet, but , again, it was based on names:
John Knifton 