English Electric Whetstone housed two major departments, the Mechanical Engineering Laboratory and the Atomic Power Division. Their first digital computer was a DEUCE - effectively a slightly re-engineered version of the original Pilot ACE, developed at the National Physical Laboratory by a team that was originally headed by Alan Turing. It was a physically quite large machine, built from valves (vacuum tubes) and using mercury delay lines for high speed storage (about four hundred 32-bit words) and a magnetic drum (8k words, I believe). It was air-cooled, with a large fan under the floor pulling in air from outside, which was then blown over the electronics and allowed to escape into the computer room.
Many stories can be told about the DEUCE, but the most memorable incident at Whetstone was the following. The computer was run overnight by a small operating staff, who recorded their activities in a log book. I and my colleagues were in the habit of checking this log book each morning, and at one time noticed that over a period of a few days there were a gradually growing number of reports of the machine failing, and of a nasty smell - but none of us connected these facts, or succeeded in tracking their cause. Then one day the underfloor fan started becoming somewhat noisier, the smell increased dramatically, and soon afterwards the machine failed abruptly and spectacularly, with red lights all over the power distribution board.
What had happened was there had been a break in a sewer pipe - a pipe being fed by all the toilets in the large multi-story building whose ground floor housed the computer room. The sewage gradually backed up, and then overflowed into the hole in the ground housing the fan, and then into the fan itself, so as to be distributed evenly and efficiently - for a while at least - around the whole computer!
It took days to dry out and disinfect the machine - but it was returned to service, though the maintenance engineer never lived down the incident.
Brian Randell, Computing Laboratory, University of Newcastle upon Tyne, UK