British aviation industry - Not the industry as a whole, but the belief that if it didn't come into hard times during the turn of the 1950s/1960s, the UK would be an undisputed global aircraft-producing powerhouse to this day.
British space program - Not the endeavour as a whole (since the programme was actually fairly succesful), but the belief that if Harold Wilson hadn't axed it at the turn of the 1960s/1970s, Britain would nowadays be a space-faring superpower envied by all.