Why was Bletchley Park able to break the German enigma codes?
There were many contributing factors that helped the team at Bletchley Park to break the enigma code, all of which were needed to break it.
The first thing that started them off was some help from the Poles. A polish spy has been in the German army and in 1931 stole documents relating to the enigma machine. Polish mathematicians, one of which was Rejewerki, built 2 replicas of the enigma machine and then gave it to Britain. This was a great help as we now knew what it looked like and how it worked.
Another thing that helped the team to break the code was the several flaws that were in the enigma machine. When the letter was put in it could never represent itself, which meant that there was in fact only 25 letters; it could be not 26. If a message was shorter than 26 letters then the second and third wheels would not move, hence there were fewer possibilities to the code. It was proven that the machine could not actually make a truly random series. All of these flaws in the machine helped towards the code being broken.