Two unbroadcast pilot episodes were produced. The first is missing, but the second is held within BBC archives.
That Was The Week That Was was officially scheduled in a 50 minute timeslot, but more often than not ran longer than its official length. This was possible as it was the last programme broadcast before television closed down for the evening.
At one point in the run, BBC executives scheduled an American drama series to broadcast after TW3, before the evening's television closure. The TW3 team were so incensed by the curtailing of their run-time that they obtained detailed plot breakdowns of the drama series and would read out the story of each episode during the TW3 preceding it. Seeing understandably declining viewing figures, BBC schedulers eventually removed the drama from that timeslot.
That Was The Week That Was was officially a factual rather than entertainment or comedy programme, being a product of the BBC's Current Affairs department, not Light Entertainment.
Although producer Ned Sherrin was very much the driving force behind the TW3 that came to screen, the programme's creation was instigated by BBC Director-General Hugh Carleton-Greene, who was keen the corporation should move away from the cosiness of the 1950s, following the huge success of Beyond The Fringe in 1961 and 1962.
Source: The Radio Times Guide To TV Comedy, Mark Lewisohn