Testery
The section at Bletchley Park that broke the Lorenz cipher by hand — the laborious half of the job, and the half no machine could take over.
Named after Major Ralph Tester and formed in the autumn of 1941 to read the teleprinter traffic of the German high command. The division of labour with the neighbouring Newmanry was sharp: the machines over there found the chi-wheel start positions statistically, and the Testery then worked out the remaining wheel settings with paper, pencil and pattern recognition. Only at that point was there any readable German.
Peter Hilton, Jerry Roberts and Donald Michie all sat in it — Michie went on to become one of Britain's first AI researchers. The section grew past a hundred people and ran the last mile every day for the rest of the war. Posterity has mostly wanted to talk about Colossus instead, which is the usual outcome when a machine and a roomful of people share the credit for something.