
Our story
HMGCC performs a vital function for government. Our teams problem-solve national security tech challenges, using both in-house expertise and outside innovation.

Our story
HMGCC performs a vital function for government. Our teams problem-solve national security tech challenges, using both in-house expertise and outside innovation.
Our story began in 1938. On the eve of war, we were created to help set up a new secure communications system through which encrypted messages could be safely sent.
Today our remit has expanded hugely. Over the decades, our work has become increasingly valued. As a government organisation, we have carved a reputation in being able to find solutions for the toughest tech problems – even the seemingly impossible.
Past, present and future
Take a look at some of the key milestones in our story:
The very beginning
In 1938, a team was set up to maintain secure communications with overseas outposts in the event of war, as an alternative to morse code. Instead, a private network was used, sending encrypted messages over a short-wave radio.
Alan Turing’s time at Hanslope Park
Although Alan Turing is more famously associated with work at Bletchley Park, he also has strong links with Hanslope Park’s wartime heritage.
The brilliant mind of Alan Turing is already synonymous with transformative wartime discoveries – most notably his work on cracking the German Enigma code. But his contributions did not end at Bletchley Park.
Turing arrived at Hanslope Park in 1944 where he worked on the speech encryption system known as Delilah.
In 1943, Turing had visited Bell Labs in the USA where he saw a speech encryption system called SIGSALY, a device which demonstrated many firsts in communications technology.
At Hanslope, Turing worked on a smaller, lighter speech encryption system alongside Donald Bayley – a recent graduate in electronic engineering. Their design made use of some of the concepts pioneered in the American SIGSALY, but added other firsts in its technology.

What was it like at Hanslope Park in the 1940s?
From what we understand, with most staff living on site, there was an active social life, with opportunities to play chess and card games in the mess, and even to attend dances. Turing would give evening lectures on mathematics and circuit design. It is believed Turing took an active part in the social life on site and was nicknamed ’the prof’. Unlike Bletchley Park, Hanslope was run as a pseudo military establishment, although in a less formal way than a real military base. Turing is believed to have first lived in a room on the top floor of Park House, and then later in a cottage on the grounds. His workspace was in the main laboratory which once stood on site at Hanslope Park. Since 2022, our engineers have been supporting a team of volunteers who have been working on a rebuild of Delilah. This was displayed for the first time in 2024 as part of an event hosted by Turing’s nephew Sir Dermot Turing. We are proud to share some of Turing’s lesser-known wartime past, as an example of the continuing history of technological brilliance and invention at HMGCC.
Image Crown Copyright - FCDO Services

By the end of World War Two, Turing and Bayley had succeeded in making a working prototype.
They would demonstrate the system in operation to high level visitors, usually by playing a recording of a Churchill speech through it.
The actual design is made up of a mix of outwardly simple circuit elements. However, the clever use of the way in which they interact and are used for different functions when transmitting or receiving makes the overall design complex. The approach did help in keeping the size small and the power consumption low. Unlike SIGSALY, Delilah will fit on a desk and can be powered from a normal wall socket.
Turing ran a competition to give the new speech encryption project a name. This was won by Robin Gandy, who suggested it should be called Delilah as she was the ‘biblical deceiver of men.’
In recent years, HMGCC has been home to the Delilah Rebuild Project, run by a team of volunteers led by John Harper. The rebuild project was based on original notes left by Alan Turing and engineer Don Bayley. The rebuilt Delilah can be seen in the photograph opposite.
