This is a download from the BBC. To find out more, visit bbc.co.uk slash radio4.

Wrong. Is it correct that you got something wrong about Powell's exclusion principle?

It is an interesting question, actually. It's possible that I got it wrong.

It's also possible that I didn't get it wrong, and that is the uncertainty principle.

And that answer applies to every single question any of you have about contemporary physics.

And on my right, a man who has never said anything wrong about Powell's exclusion principle,

but also hasn't said anything right about it either because he never said anything about it at all.

Is Robinans? So today, in a bid to piggyback on the popularity of Downton Abbey,

we look at another flamboyant English estate, but rather perpetuating the myth that all old

Dowager duchts is a catty, witting, and brimming full of bon mose. Our estate is one where

mathematical geniuses, poor know, were seemingly impenetrable codes, and somehow revealed their

meanings. We are, of course, talking about Bletchley Park and the breaking of the Enigma code.

We'll be talking about the mathematics of codes and exploring how the challenges of wartime

led to the modern computer age. A new age of enlightenment. There's opened the world's eyes to

suppose pornography and arguments and caps lock.

So today's code breaking guests are...

Did anybody work that out?

I just thought that dolphin was chatty.

Oh, for those of you who are not O'Fay with Mors Code.

Our first guest is the author of Firmitz Lars Theorem and the code book. He's also the owner of

his very own Enigma machine. Also, a popular pedant when it comes to scientifically and accurate

pop lyrics. Most famously, he changed Katie Melua's lyric of, we are 12 billion light years from

...