Top Secret for Senior Officer, immediate.

Decipher and pass to all relevant sections.

29th of May,

Intelligence Insight, number 0.07.

Welcome to this Bletchley Park Intelligence Insight.

We return in this episode to the Built-At Symposium that was held at Bletchley Park in 2017 on the centenary of his birth.

Again, we bring you one of the many talks given that day, but for the first time, in full.

Bill Tut's breaking of the Lorentz machine led to the codebreakers at Bletchley Park,

being able to read the messages being sent between Hitler, the German High Command and the generals in the field.

In his talk, our research historian, Dr David Kenyon, looked at why this was so important

to the Allied planners.

Focusing specifically on how intelligence derived from Tony decrypts played a role in

D-Day, he asked the question, how fishy was ultra.

To find out even more about the work of the Western Front Committee and the planning for D-Day,

why not go back and listen to episode 88,

The Tide of Victory,

where we looked at this in even greater detail. So moving on to our next speaker, I'm very delighted to introduce our very own research historian, Dr David Kenyon.

Thank you to Tony for that wonderful presentation. I am going to pick up on some of the issues that he presented in terms of the industrialisation of code breaking and in terms of this integration of the different intelligence sources.

What I'm going to attempt to do is, as the title describes, answer the question, how fishy was ultra. That translates to mean

what was the contribution of Lorentz in particular fish traffic to battlefield intelligence. How much of

the messages that were being sent to commanders in the field, particularly in 1944 Montgomery,

Patton in France, for example,

...