CHAPTER 17

Ultra revelations

brian randell

I

n 1974 and 1975 two books (The Ultra Secret and Bodyguard of Lies) were published.

These books alerted the general public for the first time to some of the secrets of Bletchley

Park’s wartime activities, and caused a great sensation. These developments provided me

with an excuse to enquire again about the possibility of persuading the British government to

declassify the Colossus project. This second account describes how, following a partial such

declassification, I received official permission in July 1975 to undertake and publish the results

of a detailed investigation into the work of the project. As a consequence, at the 1976 Los

Alamos Conference on the History of Computing I was able to describe in some detail, for the

first time, how Tommy Flowers led the work at the Post Office Dollis Hill Research Station on

the construction of a series of special-purpose electronic computers for Bletchley Park, and to

discuss how these fitted into the overall history of the development of the modern electronic

computer. The present chapter describes the course of this further investigation.^1

Introduction

In the spring of 1974 the official ban on any reference to Ultra, a code name for information

obtained at Bletchley Park from decrypted German message traffic, was relaxed somewhat,

and Frederick Winterbotham’s book The Ultra Secret was published.^2 Described as the ‘story

of how, during World War II, the highest form of intelligence, obtained from the “breaking”

of the supposedly “unbreakable” German machine cyphers, was “processed” and distributed

with complete security to President Roosevelt, Winston Churchill, and all the principal Chiefs

of Staff and commanders in the field throughout the war’, this book caused a sensation, and

brought Bletchley Park, the Enigma cipher machine, and the impact on the war of the breaking

of wartime Enigma traffic, to the general public’s attention in a big way. The book’s single refer-

ence to computers came in the statement:

It is no longer a secret that the backroom boys of Bletchley used the new science of electronics

to help them . . . I am not of the computer age nor do I attempt to understand them, but early

in 1940 I was ushered with great solemnity into the shrine where stood a bronze coloured face,

like some Eastern Goddess who was destined to become the oracle of Bletchley.