Dorothy Du Boisson

Dorothy Du Boisson, MBE (26 November 1919 – 1 February 2013) was a code breaker stationed at Bletchley Park during World War II.

Bletchley Park Du Boisson joined the Women's Royal Naval Service (known as WRNS) during WWII and was stationed at the Newmanry sector of Bletchley Park, England. With others she operated code-breaking machines, such as the Tunny machine Heath Robinson. She was one of only four operators working with the Tunny but, to work efficiently, she had to learn how to operate the Heath Robinson as well. After the Colossus computer was developed, she operated it under the direction of a cryptographer.

When more Wrens were posted, Du Boisson came off the machines and went into the Ops Rooms as a registrar. She was responsible for logging the tapes in and out and distributing them to the machines. Since she was one of only two people working in the Ops room, Du Boisson had a tremendous amount of work to do. She recorded the date and identity of each tape used on the Colossus and Tunny. She knew exactly where each tape was and the machine time spent on it. Moreover, she was also responsible for unwinding tapes into buckets and joining them into a loop. This was an essential step for operation, since the tape might not stand up to the speed of the machine. After many experiments, Du Boisson found a unique way to strengthen it by using a special glue, a warm clamp, and French chalk. After the war, the machines were smashed into fragments on the orders of Churchill. Later, Du Boisson worked as a typist in the Air Ministry.

Most of the workers were between 20 and 22 years of age. They attended training sessions to get more familiar with the machines, how they operate and the maintenance procedures. The working shifts could last up to 70 hours per week