Intelligent readers will have Deep Blue sussed just from a reading of the teaser. Beside a quiet English seaside village in the mid-1970s, there's something in the sea which is adversely changing the villagers' appearance and behaviour. Could it be some alien invader "feeding on human energy", do you think?

That Doctor Who has borrowed from other genres - such as the B-movies which initiated this type of story by disguising political fears as horror and science fiction - is widely acknowledged. Unfortunately, other than a hint of Star Trek's Borg, Deep Blue's single inspiration seems to be Doctor Who itself, incorporating as it does only the mildest of twists on the overused notion of possession, while stealing jokes and scenes from televised episodes. Content and intent match well, as this book is more parasitical than most in feeding off the tv show. Like Mark Morris's inexplicably popular debut The Bodysnatchers - and that's a title which could apply to this novel as much as the earlier work - it's pastiche Doctor Who with little to add to the source material.

There has been too much of this returning to the well in the BBC range of books. Some might regard giving a UNIT officer in this novel the name "Corporal Manning" as a harmless in-joke - and it might be, if only the range wasn't already completely infested with such details. It surely can't be healthy for so many novels to feed off the corpse of the show to such an extent. The gene pool is already showing signs of stagnation, even in some of the better novels - of which Deep Blue certainly isn't one.

The pop-cultural references used to establish the period are so over-stressed as to be unintentionally funny, characters are introduced only to turn into parasite-fodder within pages, the fifth Doctor isn't convincingly depicted - especially when kept out of the action so much - and Turlough is insipid. To the author's credit, Tegan's plot strand is reasonably interesting, there's a surprise toward the end and it's an inoffensively easy read - but that's just not good enough.