This is a wonderful documentary that shouldn’t be missed.
Alan Turning gets all the praise, but Welchman was right up at Turing’s level.
Before Enigma was ever cracked, before there were any Bombes for decoding …
… Welchman was observant enough to notice a crack in the encrypted communications …
… and this allowed Bletchley to have an insight into the German communications system …
… which was vital for assessing the types of communications flowing through it, even though they were all “impossibly” encrypted.
His second major contribution (that we know about), was a special electrical circuit …
… that increased the processing efficiency of the Bombes. What had taken hours and hours previously could be done sometimes within minutes!
Unfortunately, in his later life — just like Turing — he was hounded by an ungrateful and vindictive government.
You see, he wrote a book that revealed some of his initial insights.
And they were still considered state secrets.
He was hounded despite the fact he helped America create a defense communications system that the Soviets — or any other nation — couldn’t match.
He was fired from his job and had his secret clearance revoked.
And was constantly pressured by American and British intelligence agencies.
Instead of getting the recognition and gratitude he was due, he died virtually unknown, just about forgotten, and nearly a broken man.
This should never happen to anyone ever again.
Mike Cane's Atomic Supermen 
I’ve read just about every book about this subject and this documentary did a great deal of adding new info the overall story. It is a great shame that he was treated in the way that he was. However; he knew what he was signing up to when he started down this road. I do feel somewhat sympathetic to his plight in that a number of colleagues were making some money off the back of their own involvement in the story, so why could he not do the same?
Having worked briefly on Naval successors to the Enigma/Colossus machines during the late 60’s / early 70’s, a) you never actually realise the significance of the equipment you’re working on at the actual time – it’s just another bit of kit! b) years later when you see the connections appearing through various books/films, it does make you think about what you did work on with a different view point and c) I signed the official secrets act when I joined the Navy and while I had nowhere near as much detailed or wide-ranging knowledge as many others, I am still covered by it some 50 years later.
Great post by the way.
Thanks for your additional insights.