Written by Malcolm Hulke, based on his scripts for the 1974 TV serial Invasion of the Dinosaurs.

Malcolm Hulke’s final TV story becomes one of his finest novelisations. Freed from the dodgy dinosaur effects, it’s a taut and effective novel that crystallises many of the author’s favourite themes: the need to find a middle way between extremes (here, destroying the world through pollution or nuclear holocaust, or else exterminating humankind so a chosen few can bring about their Golden Age); the lack of straightforward villains, and the appearance of ancient reptiles to the present day.

As in The Cave-Monsters, Hulke includes a prologue explaining the history of the dinosaurs, and adds a sequence of a hapless Glaswegian called Shughie caught up in the initial stages of the invasion setting up for the Doctor and Sarah Jane’s arrival in a deserted London. This scene setting efficiently provides a backdrop that means the rest of the novel doesn’t have to constantly dwell on sequences of UNIT-on-dinosaur action, and frees Hulke the time to focus on characterisation, which is extremely effective.

The regulars do well, with Hulke making this very much a Sarah Jane novel – she does all the heavy lifting of investigation and adventuring, blowing open the conspiracy, winning over allies on the “spaceship” heading for New Earth, and engineering her own escape as often as she needs to rely on the Doctor’s help. This allows the Doctor to pootle about in the background with the dinosaurs, and the Brigadier to be generally reliable but baffled (mostly saying “good point” as General Finch and the Doctor discuss tactics). Hulke sequelises his own adaptation of The Green Death, leaning into the idea of Mike Yates greatly affected by his experience of brainwashing, and falling under Grover’s spell as he recuperated.

On the other side – there are no villains as such (even the heavy Butler turns out to be an ex-fireman who picked up his facial scar heroically saving a child in the line of duty). Grover and his allies are genuinely convinced that Earth is a busted flush and that only they offer salvation for humanity. They have become radicalised by their own righteousness: “We shall take the good, but leave the evil behind,” claims Adam – to which Sarah tartly replies, “And who decides which is which?” before reflecting, “Beware people who know they are right, like Oliver Cromwell. For the good of Humanity, those people sometimes do murder.” Anyone who’s seen Game of Thrones might recognise this argument almost word for word. Hulke even tries to get into the mind of the prehistoric monsters, with sequences from the point of view of a T-Rex and a stegosaurus. Only Whitaker comes across as unlikeable: his vain, pouting, prima donna-ish behaviour exasperates his collaborators, and the whiff of lavender is made almost explicit when he declares the Doctor to be “terribly handsome”.

Garnished with deadpan humour, the result is perhaps Hulke’s best book, and a strong contender for the finest Target to date. Grade One.

Next Time: Doctor Who And… The Tenth Planet.