I recently visited a place in England which was very top secret during WW2. It was where the government set up a special department for breaking codes used by its enemies: Bletchley Park. Wartime communications, especially military, were normally sent in some coded fashion. This has been the way for many hundreds of years; a way of trying to prevent your enemies knowing what you are planning either defensively or against them directly.
We’re all familiar with the idea of a code: something which changes the letters of normal words into something which hopefully is hard to decipher if the message falls into enemy hands. A simple code would be like this: nwpf usppqt up uif csjehf. It means “move troops to the bridge”. You can probably see it’s just a transposing of the normal letter by one to the next letter in the alphabet. Nothing else has been done so the same number of letters appear in each word once it is coded. A slightly harder version might be npw fus ppq tup uif csj ehf where the letters are grouped into threes and it is much harder to see how the words are made up. Of course there are much more complex versions of coding and ones based on some mathematical formula. During WW2 the Germans had invented a machine which produced one of the most complicated forms of coding. It needed three wheels to be placed into the coding machine each set to a certain letter of the alphabet. Once in place when the operator pressed say the letter “a” out would come “t” and then after “b” was pressed out would come “m” say and so on. The receiver of the message then put the same three wheels in at the same positions and typed the coded letter and out would come the real one. The only way you could fathom it out would be if you know which wheel settings had been used and in which of the three slots. Anyway the job of the folks at Bletchley Park was to try and figure out how the wheels altered the normal letter into the coded one. There’s too much detail to go into here but here is a picture of the front of the machine they built to try and duplicate what the German coding machine was doing.
Alan Turing was the man in charge of the project and the machine was called a “bombe”. (The word bombe came from anglicising the name of an earlier simpler machine used by Polish code breakers. They had called theirs bomba kryptologiczna). Although it looks like something sat on a table it is big - it actually reaches to the floor and is taller than a person.
It’s amazing seeing all the wires making the connections to wonder how Turing’s team could have possibly been able to work out how to make it.
Bletchley Park is a very big site and if you wanted to read all the info boards you’d need a whole day. I couldn’t spend the whole day but I was there about 5 hours. A number of the huts that were used during the war have been made into exhibition areas on different subjects. One in particular was very interesting because it was on a subject which many people know little or nothing about – how pigeons were used in the war. If you read my post from 18.7.12 about bird droppings you will remember I was not very complimentary about pigeons because of the mess they make on our cars, houses and washing. However, one of the films I saw showed how during the war there were times when homing pigeons were essential: when radio silence had to be maintained. Agents on the Continent would use them to send messages back to England with information about troop movements and requirements for the resistance organisations. The use of them was taken so seriously that the occupying forces used snipers to try and shoot down pigeons flying over the area. Anyone keeping pigeons would of course be under suspicion. Paratroopers sometimes carried them in their uniform to release when they had landed. I was surprised to learn that flying relatively short distances over The Channel back to England they could fly at speeds of 60mph.
Pigeons have been used for carrying messages for hundreds of years (different ones of course as they don’t live for hundreds of years individually!). One ancient ruler actually set up a regular messenger service using carrier pigeons between Baghdad & Syria. They’ve been used at various times throughout history for carrying valuable information; and scientists still don’t really know how they find their directions. A number of theories have been postulated: inbuilt compass, using invisible magnetic lines & using physical geographical features like roads or rivers. Some appear to follow roads or rivers when trying to get their bearings. Anyway however they do it, it seems to work.
The usefulness of carrier pigeons led to a number of measures being taken by both sides in WW2. Look at this poster headed “Defence of the Realm”.
You could get 6 months in prison or £100 fine for shooting one according to this poster issued in Leeds. Also the government offered a reward of £5 for info leading to a person being convicted of shooting a homing pigeon.
This poster I assume was done for publicity purposes to frighten the local community. This man as you can see was shot the day before the notice was put up. He was shot because they believed he had released a pigeon with a message for England. Pigeons’ abilities were taken very seriously by both sides. However the film mentioned that there were horrendous numbers of casualties & birds which didn’t make it home. Some may have been shot; some may have been killed by natural predators; some may just have not found their way back. Despite this they clearly supplied enough good intelligence to keep the idea going and homing birds have continued to be used even in conflicts of recent times.
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