“You might’ve been all kinds of a gay boy before, but you’re married to me now!”

Kids, eh? When they’re not having nightmares about getting locked in asylums, they’re banging on about long-supressed childhood traumas. If you ask me, a bit of bullying is exactly what they need. Or if not that, then at least a shun or two.

And so welcome to finishing school in the mid 60s, where one of those young ladies, Janet (Jennie Linden) is being pestered by nocturnal voices (“Janet, I’m waiting”) and dreaming of getting trapped in a dark room with a nutty old woman.

“Now they’ve got us both! We’re both mad, aren’t we?!”

Cue hysterics. Which is fair enough.

Now, before we get into the bones of this story, it’s fair to warn you that the proceedings chronicled by this film and any actual internal logic are very much strangers. Just remember that later on, otherwise you’re going to get annoyed pretty quickly. Best not think too much about what unfurls in the next 80 minutes or so. Trust me. You’ll enjoy it more that way.

So, Janet is suffering from night terrors, and the school thinks the best approach is send her home to recover. Why this might not be the greatest idea will become apparent, but let’s just put it this way - the school’s commitment to the welfare of its students isn’t exactly first-rate. Given Janet’s family history (traumatic, as we’ll discover) you’d think they’d have an inkling. But no.

Janet is accompanied home by her teacher, Miss Lewis (Brenda Bruce). They’re picked up from the railway station by a chauffeur-driven Rolls -Royce (flash), and on arrival at the family pile (which is a very piley old pile indeed), Miss Lewis is finally informed about Janet’s traumatic childhood inciting incident.

She walked into her parents’ bedroom to find her mother, knife in hand, standing over the body of her dead father.

“She was 11, Miss. 11 years old,” the housekeeper (Irene Richmond) tells Miss Lewis. “Can you imagine what a thing like that might do to the mind of a child?”

To which the correct answer is “yes, and it might have been worth informing the school about this as it could have helped earlier”, but never mind.

Janet is worried that she might have inherited insanity from her mother, who is locked in the asylum they passed on their way from the station. Once again, not exactly excellent childcare going on, there. Won’t somebody think of the child?

WELL, it turns out a number of people ARE, and not exactly with her ongoing health and wellbeing a paramount consideration.

Janet’s bad dreams and sleepwalking continue (“I had a dream… at least I think it was a dream. But if it was a dream, what am I doing here?”), and the next day Miss Lewis decides that’s enough caring, thank-you-very-much, and leaves.

Unsurprisingly, at this point things ramp up considerably. Despite the apparent best intentions of Janet’s new carer Grace (Moira Redmond), the girl’s mental health spirals downward. She wakes to see a strange woman in her room (this time we see her too, and to be fair, the scene properly freaked this reviewer out). Following the spooky woman, she finds her stabbed to death in the room where her father died. Cue more hysterics.

The haunting continues (“I don’t even know who she is! I don’t even know who she is! How can you dream about someone you don’t know?”), until Janet can take no more and tries to take her own life.

By now her uncle Henry (David Knight) has arrived, and Janet clearly has an extreme crush on the man. The next day the family all seem very keen to ignore her wrist-slashing activities from the previous evening, but things take a turn for the even-more tragic when Henry introduces his new wife (Clytie Jessop)… who is the woman who has been haunting Janet. Unfortunately, there’s a handy knife nearby and Janet’s night time visions appear to have been a chilling premonition of the woman’s murder.

But that isn’t the end of the shenanigans, in fact it’s only the start. The haunting is NOT everything it is cracked up to be. As is often the case in these Hammer psychodramas, it’s all a convoluted plot. But even as, against all sense and logic, the plan succeeds, the bad guys start to fall out – and the spooky figures start appearing again.

Nightmare is yet another hugely entertaining Hammer thriller. Utterly bonkers, and held together with the thinnest of threads, it’s also genuinely spooky and wonderfully atmospheric. Once things start to unravel it is marvellously entertaining, and to give it credit, the film keeps you guessing right until the end.