With the arrival of Terror Of The Zygons it was clear it would be up against new Gerry Anderson series Space:1999. The hope and "conspiracy theory" was that Doctor Who's science fiction adventure tale would "scupper" Space:1999. Writer and TV historian Simon Farquhar offered some interesting thoughts from a British perspective in the documentary Scotch Mist In Sussex found on the DVD for Terror Of The Zygons regarding Doctor Who's brief dip in the ratings and then ultimate success:
"Within a few weeks they were back to normal. And Space:1999 sort of really never made the impact that it was intended to. All of those shows that Lou Grade did which were designed to appeal to Britain and America, most of them, as someone said, landed in the middle of the Atlantic with a dull splash. Didn't have heart, didn't have the soul of Doctor Who. Martin Landau wasn't really any competition for Tom Baker. Barbara Bain was certainly no competition for Liz Sladen. So I don't really think it had a hope."
As it has turned out of course history has been much kinder to our beloved Space:1999, a series I loved equally with Doctor Who. I tend to think Space:1999 has held up better technically, but that is simply a matter of production quality. Both the classic Doctor Who and Space:1999 deliver on ideas and stories equally well.