Here’s Johnny Byrne talking about ‘Warriors of the Deep’ and, in particular, his approach to the Silurians and the Sea Devils (who he refers to as aliens!). His comments about the need for the Silurians to have a more human face are interesting, given certain rumours about the new series…
“At some point in ‘Doctor Who’, monsters became mandatory whether they were needed or not, because there was some sort of weird belief among the higher echelons that this was what made children flock to the show. There should have been a better way to represent the aliens in ‘Warriors of the Deep’ (the Silurians and the Sea Devils), rather than the way we did. I think to make the story believable, the Silurians needed to be more humanoid in their form, in their aspect, so we understood them in a human sense, and the Sea Devils should have been much more of a physical threat. Instead of the Sea Devils being hunters and killers, SAS types, we got these sort of lumbering chaps doing their best in very heavy costumes.
“Did we really need the Myrka? It’s a question I don’t think I can answer, even though I wrote the Myrka. Would it have been better without the Myrka? The Myrka would come into any situation that required physical force, and the Myrka would cause chaos, and then the Silurians would come in and say ‘Oh, isn’t this dreadful, we shouldn’t have done this but we had no choice’. The Myrka, as it appeared, rather destroyed that illusion, because first of all it showed the Silurians to be idiots, to have created anything so pathetic and ineffective, and it became the most despised and hated creature in the history of ‘Doctor Who’.”
Doctor Who Interview Archive 