When I got a telly we had no aerial, but I discovered that if I or one of the children stood by it you could get a picture. So I had to make a statue that could stand by the telly. ↗
I was well aware of the fact that once you appeared in Doctor Who as something else, you were ruled out for the part of the Doctor: that was a kind of well known thing in the business. ↗
A major one which no one can overlook is technological and based on inventions and discoveries which have altered the whole basis of production and deeply affected social relations. ↗