Gareth Negus watches the version of Pride and Prejudice where a person is sought after not for their wealth or status but for their brains.

It is a truth universally acknowledged that any article about any version of Pride and Prejudice should reference the novel’s opening line, so I decided to get it out of the way. It’s also true that movie producers would have preferred Jane Austen to have lived long enough to finish a few more novels that could be adapted and reimagined on a regular basis, but she didn’t, so we end up with peculiar ideas like this.

Pride and Prejudice and Zombies is based on a novel by Seth Grahame-Smith (for which Austen receives co-writing credit) which sets the original story against the backdrop of a zombie apocalypse. This sounds like an idea that, while potentially amusing, might work better as a five minute segment in a sketch comedy show. Can a full-length feature satisfyingly meld flesh-munching horror and romantic comedy? On this evidence, no, not really, though it does come surprisingly close.

Lily James stars as Elizabeth Bennet, one of four sisters who live with their parents (Sally Phillips and Charles Dance). Mrs Bennet is focussed on getting her daughters married to wealthy men to secure the family’s future; Mr Bennet is more concerned with their not being eaten by zombies, to the extent that he has had them trained in martial arts in China, rather than the more socially acceptable Japan. As in the book, Lizzie meets Mr Darcy (here a ruthless zombie hunting soldier, played by Sam Riley with a voice so raspy that it brought to mind Stephen McHattie). She takes an instant dislike to him, but – does anyone really need a spoiler warning on this? – love gradually starts to blossom.

The plot turns of the original novel are all present and correct, but the need to include zombie attacks (they seem to turn up uninvited at every ball in England) means they are rattled through at a fair old pace. The actors would all be acceptable casting in a straight Austen adaptation (special mention to Matt Smith, apparently enjoying himself immensely as Parson Collins) but this only adds to the feeling that the zombies are an unwelcome distraction from the romantic plotline.

After an hour or so, things settle down and the two strands of narrative begin to work together better. A verbal battle between Elizabeth and Darcy is played out during a physical battle, as the pair test their combat prowess as well as their wits. A plot about a potential leader for the zombies (whose identity is not hard to guess) is interwoven with the original in a fairly logical manner. But the film still suffers from abrupt tonal shifts: Darcy’s letter to Elizabeth segues jarringly from a heartfelt explanation of his previous behaviour, to news of the imminent fall of London to the undead hordes.

Overall, it’s watchable fun, but you may find yourself wondering who it’s for. Nowhere near scary enough to work as a horror film (a number of kills take place off screen, as though they were going for the lowest rating possible), the zombies nevertheless manage to distract from both the romance and the comedy. A curiosity at best, then, but perhaps the mix will make it the ideal Valentine’s Day choice for couples of differing tastes.

Pride and Prejudice and Zombies is released in the UK tomorrow.

Gareth Negus tweets at @garethnegus