Laura Morgan finds that the sum of the parts of Jean-Pierre Jeunet’s latest offering is slightly less than the whole.

Do you have any films which you use as barometers, to compare other films against and decide whether they’re any good? The first film I can remember identifying for this purpose was The Fugitive, which I decided was exactly as good as a thriller needed to be. No better, no worse. Therefore “is it better than The Fugitive?” was the only question I needed to ask myself when unsure about whether I thought a film was any good.

I have two yardsticks for children’s films. One is 2007’s ungarlanded and widely forgotten Nancy Drew, which I went along to full of anticipation, having been a childhood fan of the books. As a literary adaptation it was disappointing; as a mystery story for youngish children it was fine. Not good, not bad. Fine. The second children’s film I measure others against is Lemony Snickett’s A Series Of Unfortunate Events, which fell victim to this fate for no better reason than that it came out somewhere in the middle of the indomitable march of the Harry Potter films. Like them it featured a starry cast (Meryl Streep! Jim Carrey! Uh, Jude Law!) in a large-scale adaptation of a fairy-tale-ish children’s book. The Harry Potter films were bedazzling, bewitching; buckets of fun: A Series Of Unfortunate Events was fine. Not great, not awful. Fine.

About seven-eighths of the way through The Young And Prodigious T.S. Spivet I decided I had another zero-sum game on my hands. Children would like it, I thought, but it might not quite hold together enough to appeal to an adult audience. And then a character said “Fuck”, and I had to reassess my position. Personally, I have no problem with saying “fuck” in front of (or indeed at) children, but I know there are those who hold a different view, and the smart folks at the BBFC have given it a 12A rating, which is probably about right, what with the “fuck” and all, but it’s a shame, because I think that, “fuck” aside, the most appreciative audience for this film is probably to be found among eight- and nine-year-olds.

It’s not a bad film. Some things about it are good. Kyle Catlett, as our eponymous hero, is pretty good given his weeniness and the amount of action he has to carry. Niamh Wilson, as his scathing elder sister Gracie, is excellent and I am going to come out now and tip her for a bright future. Helena Bonham Carter is fine – not amazing, not terrible; fine – as T.S’s mother Dr Clair, and Callum Keith Rennie is menacingly good as his (unnamed) father, although he and HBC don’t ever seem, quite, to be in the same film.

It looks good, although the 3D adds very little (but it doesn’t detract either. The 3D is neutral). The story is good. The faintly physically hideous supporting cast (Dick Tracy came to my mind, unbidden) are uniformly good. But somehow, none of it quite seems to fit together.

I realise I’ve forgotten to tell you anything much about the film. T.S. is a boy genius, who has invented a perpetual motion machine and is invited by the Smithsonian Institute, who don’t know that he’s barely out of short trousers, to come and receive an award in recognition of his work. T.S. has a flouncy teenage sister who has accidentally fallen out of a John Hughes movie, a scientist mother and a cowboy father. He also has a deceased twin brother who, we learn early on, died in an accident in which T.S. was somehow implicated. This set-up gives us a confused melange of road movie, comedy and learn-and-grow family saga which almost works, and then somehow doesn’t, because while the set-pieces are good and funny and well-done, there is nothing linking them together to form anything that feels coherent or meaningful as a whole.

What they should have done was stick with the funny, and leave the poignant out altogether. The moment at which I thought “actually, this is pretty terrible” was when our hero gazes earnestly at rain trickling down a window pane and says, in voiceover: “The amazing thing about water drops is that they always take the path of least resistance. For humans it’s exactly the opposite.”

Well, I mean, what? I tried, and am still trying, to work out what that even might be supposed to mean, and I’m afraid I’ve failed completely. It’s just a string of words. In contrast, when the film is funny it really is funny, and it’s this mismatched attempt at drawing in something serious or solemn that drags down what could otherwise be a sweet and funny film. Happily, the seriosity constitutes a smallish proportion of the whole, so I have no real hesitation in advising you to take your eight-year-old along to see it, always assuming s/he can cope with the occasional “fuck”.

The Young And Prodigious T.S. Spivet is out on Friday.