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The From the home of the codebreakers and the birthplace of modern computing, this is the Bletchley Park podcast.

Welcome to the May 2025 episode of the Bletchley Park podcast, Dollis Hill Days.

During World War II, Bletchley Park collaborated with several external engineering institutions

in developing the famous code-breaking machines such

as the bombs and colossus. One such institution was the Post Office Research Station at

Dollis Hill in London. In 2022, the previously secret war diaries of the research station were

released online to the public by BT, the successor to GPO Telecommunications.

In this episode, we're joined by James Elder, an archivist from BT Group Archives, as well as

our own research historian Dr David Kenyon, to find out what information the diaries can reveal

about this secret collaboration. Many thanks to Dr Ben Thompson for voicing extracts from the War Diary.

We'll start with you, David, and a bit of background. What was the Post Office Research Station?

The Post Office Research Station is established in 1909, and it's a place for technological research

for communications and other technologies required by the Post Office, essentially,

because at this point they're not just posting letters, they're also doing telecommunications,

so telephone, telegraph, those sorts of things.

After World War I, it moved to the location we're concerned with, which is Dollis Hill in North London.

Initially they set up there in some army timber huts, but in the 20s and early 30s, the current building,

the organisation isn't there anymore, but the building still is. There's a rather magnificent building, large structure on the top of Dollis Hill, which you can see

for miles, which was opened in 1933 by Prime Minister Ramsey-McDonnell.

And research carried on in there through the 1930s and into World War II.

And it's the World War II phase that we're particularly interested in because

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