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Decoding D-Day

Bletchley Park is famous for its codebreaking work, but did you know that Hanslope Park was crucial to its success?

Intercepting German communication

The UK government recognised the importance of intercepting radio communications before the Second World War. From 1939, they began to recruit amateur radio enthusiasts to listen into German radio transmissions. As the scale of the mission increased, the Radio Security Service (RSS) emerged to coordinate the amateurs working from home.

At first, the RSS recruits sent their intercepts to a PO Box, but as the number of intercepts grew they moved, from Wormwood Scrubs to Arkley View. In May 1942, they made their final move to Hanslope Park, and its radio intercept station became fully operational. Hanslope intercepted radio transmissions from Northern Europe, and its close proximity to Bletchley Park made it ideal for transporting intercepted messages quickly.

Hanslope during the War

Several of the recruits at Hanslope Park were amateur radio enthusiasts, who were especially skilled at hearing weak Morse Code. They became so aware of the individual radio operator’s ‘fingerprint’ that they could identify individuals and even gave them nicknames. As soon as recruits recorded intercepted messages, they sent them down to Bletchley Park by motorcycle courier.

These intercepted messages were incredibly important, especially for D-Day and the following battles. They not only showed allies that they succeeded in persuading the Germans that the invasion would be at Calais, but provided information during the invasion itself. As Hanslope Park and Bletchley Park sit so closely together, they could intercept, record and decrypt a German communication in three hours. This meant the information soldiers received was up to date.

The significance of Hanslope Park

Hanslope Park’s impact was so important that it was visited by Field Marshal Montgomery and General Eisenhower. At the end of the war, Hanslope was taken over by another department which specialised in secure communications – and we are still here today. Nowadays, FCDO Services does the opposite of intercepting communications. Instead, we develop secure IT systems and closed environments to actively prevent any interception.