- [voiceover introduction: showing a photograph of Bill Tutte]
- Narrator: This is a British mathematician called Bill Tutte. You won't have heard of him, but in 1943 he pulled off what many believe was the greatest intellectual feat of World War Two. It shortened the war and saved millions of lives. He died in 2002 without ever being officially recognised for his achievement.
- [showing a photograph of Tommy Flowers]
- Narrator: This is a former GPO engineer called Tommy Flowers. In 1944, he turned Tutte's mathematical ideas into the world's first computer. He died in 1998. Chances are, you won't have heard of him, either. Backed by the brightest talents of Bletchley Park, they allowed Britain to break a top secret machine employed by Hitler to dictate the course of the war.
- [showing a photograph of a coding machine]
- Narrator: This machine was *not* Enigma. It was something far more secret and significant. And you *definitely* won't have heard of that. This is the story of a secret war and how two men changed the world - and then disappeared from history.
- [caption at start of programme: comment made in his book "A Mathematician's Apology", 1940]
- G H Hardy: Real mathematics has no effect on war.
- [a picture of Bill Tutte's gravestone is shown]
- Keeley Hawes - Narrator: Bill Tutte's memorial is a simple headstone in a rural Canadian cemetery, and a lifetime of academic achievement. Tommy's is slightly different.
- Kenneth Flowers: My father was cremated and the ashes scattered at the crematorium.
- [a picture of the reconstructed Colossus is shown]
- Kenneth Flowers: But I think he would have recognised that his main memorial is at Bletchley Park in the reconstructed Colossus. As an engineer, to have a working machine as your memorial is the ideal thing, really.
- [a picture of a Lorenz machine is shown]
- Jerry Roberts: Hitler ordered this machine himself. It should never, ever have been broken. But the minds of Bletchley Park managed to find ways of breaking it. And this is an amazing triumph of mind over machines.
- Jack Copeland: At the end of the war, Flowers got a leading inventors' award for his war work. And this carried the monetary award of £1000, which was quite a lot of money in those days, of course. But Flowers being Flowers, he shared it with his men, and so by the time he had done that, he'd got about 350 quid for inventing the first electronic computer.