Harry Griffiths' career as a "Radio Security Service" listener

Father, Harry Griffiths, served in WW2 as a radio operator.

He was a member of the Radio Security Service based in Cornwall listening to the German Secret Service, 1939-1945. The station at which he was based was a Bletchley Park outstation. They also listened to radio intercepts of Italian and Russian Secret Service broadcasts. Operated 24/7 and could intercept morse code transmissions from the Abwehr at a rate of well over 35 words (per minute?), perhaps.

Seven stations were based in this area which were, literally, 'Ulstrasecret' (ULTRA listening stations). Stations were part of B.P. (???)

Everything done was most secret of secrets. Picked up messages that, most of the time, his colleagues wouldn't have a clue (could not understand).

He died before medals came out - wanted to tell but died before he could fully explain.

Book: "Listening to the Enemy" [Photograph of photo on front cover]