“Fun was absolutely The Big Brief!” says Chris Chibnall, writer of two episodes this autumn. “Make it a big, loud, funny romp on a great scale.” This is his fourth episode of Doctor Who after the 2007 story 42 (starring a hot-and-bothered Michelle Collins) and the Silurian two-parter two years ago in which Rory was erased by the crack in time.
What was his first reaction when showrunner Steven Moffat gave him those four words, Dinosaurs on a Spaceship? “Err, did he really just say that? Does he really mean it? How are we going to do it? And, fantastic!”
I’ve watched it several times now and each time I’ve laughed, cooed and felt choked in all the same places. I’d have loved this grandiose action-adventure when I was a nipper. It is, as Chris says, fantastic fun.
But how did the idea come about? Marcus Wilson, series producer since The Impossible Astronaut last year, explains: “At the end of series six we had a conversation with our main suppliers like [digital fx company] the Mill and [prosthetics experts] Millennium FX and went, ‘Come on, guys, what would you be really excited about doing?’ and the Mill said, ‘We’d love to do dinosaurs!’ ”
The idea was pitched to Chris, “And he just smiled and went, ‘I know what to do with that,’ ” says Marcus. “Then he fired in some requests, ‘Can I have Rory’s dad? Can I have an African game hunter?’ And we’re thinking, ‘How does all this work?’ But when the script arrived, it was exciting to see where these other elements fitted in.”
“The first pitch I gave was very much what’s ended up on screen,” continues Chris. “Which is slightly unusual on Doctor Who. You often go round the houses. But it was such a clear concept.”
Could he be as ambitious as he liked? “It would be very easy to spend £300m on this but we don’t have it. So I had to be very responsible early on and go, ‘How do we do this? How do we make it work? What can we do with the dinosaurs? We went into a lot of detail. How many on screen? How many species? Some would be practical, some CGI.”
He also admits, “I knew that title alone couldn’t sustain 45 minutes. There had to be big stuff going on elsewhere.” What adds to the fun is that the Doctor has assembled an oddball gang to assist him: not only the Ponds, but Rory’s dad Brian, Queen Nefertiti and an Edwardian big-game hunter. “The fabulous thing about Doctor Who is you can have this collision of characters you’d never have in any other show or film and put them together in the most extraordinary situation.
“The idea of an Egyptian queen on a spaceship with dinosaurs really tickled me. And I really wanted to see Rory’s family and asked Steven if I could do that, knowing we only have a few episodes left with Rory and Amy. His family background hasn’t been explored, so it seemed like a great opportunity to have some fun with that.”
Brian Williams (played by The Fast Show’s Mark Williams) is one of the successes of the episode. A reluctant traveller, he rarely goes further than the paper shop and the golf; he gets a lot of comedic and heart-warming moments, and actually looks related to Rory. “You learn a great deal more about people when they’re with their parents. It exposes them,” chuckles Chris. “Brian’s a dad figure who embodies all the fears of the dad that I will become. Inept and unhelpful but also showing a great love. And you get the impression he’s slightly keener on Amy than Rory.”
Don’t expect Dinosaurs on a Spaceship to be wall-to-wall prehistoric monsters (and do expect some surprises) but they all look amazing. The triceratops, surely everyone’s favourite dinosaur, is a thing of beauty. It’s a far cry from Doctor Who’s previous stabs at dinosaurs, back in the 1970s, which were embarrassingly dodgy.
“I don’t remember watching Invasion of the Dinosaurs  as a child, although I did see The Time Warrior, which came just before,” says Chris. “I remember more reading the book, which was superb. I’m a huge fan of [writer] Malcolm Hulke.”
Marcus only vaguely recalls Invasion of the Dinosaurs with Jon Pertwee’s Doctor. “I’m a Tom Baker child really. I remember the Loch Ness Monster [in Terror of the Zygons, 1975]. I was actually quite spooked by that. But then I was only four or five.”
Marcus concludes: “I’m sure later generations will look back at our efforts and go, ‘Is that the best they could do?’ ” Somehow I doubt that.