“There are things wrong with the church, but every job has its problems…”

Acidic black comedy, or typically crass 70s horror flick brought out with the sole aim of shocking a jaded public? The jury's still out on House Of Mortal Sin (aka The Confessional), but you can't deny that it's entertaining.

Valerie's parents are sitting watch the telly when their daughter walks in, goes upstairs and lobs herself out of the window, hitting the ground with a sickening thud. As the parents look on in horror, the camera crash-zooms onto the fluttering pages of her Bible…

As the credits roll, we're left puzzling about Valerie's fate. Did reading her Bible give her the mistaken impression she could fly like an angel? Was it just that her parents' house was in such darkness that she fell out of the window by accident? What did that note say that she hastily scribbled before departing this mortal coil?

It doesn't take much plot before we find out, but in the meantime we're treated to a brief introduction to the rest of the cast - young priest Bernard Cutler, who very nearly runs over friend Jenny (Susan Penhaligon) in his car, Jenny's boyfriend (typical 70s bloke complete with comedy cravat), who's busy moving OUT of their flat above Jenny's sister's (Stephanie Beacham) shop.

Beacham: "You're a right little charmer, aren't you?"

Boyfriend: "Get fucked."

Jenny, understandably hurt by this behaviour, decides to go to confessional (oh-oh), where she wastes no time in telling all to a Father Meldrum: "He doesn't care about my feelings, he's got other girls…" But she soon gets scared by the priest's overbearing attitude ("There's no need to be embarrassed discussing sexual matters with me…") and runs away, straight into the arms of Bob, a man with a bad jacket and an Italian sports car.

Jenny leaves Bob in her flat fr a moment when she realises that she's not only lost her keys but left her cigarettes in a phone box as well, and by he time she gets back he's been slapped about by an unseen assailant and had boiling coffee thrown in his face (an act that causes his face to explode into a bloody mess, for some reason).

As she makes her way thrugh the darkened flat, she sees a crucifix flash in the darkness, and runs away - straight into the arms of Bernard and Vanessa.

The film is already showing its typically grim 1970s attitude to everything with these few scenes. Jenny's boyfriend is a selfish womaniser, Jenny herself is a pathetic doormat, even the idealist young Bernard at one point says to Vanessa: "There are things wrong with the church, but every job has its problems…" We've also seen a Brit horror cliché turned on its head - in what other film is a crucifix shining out of the darkness a symbol of terror?

Meanwhile Jenny needs her flat keys back, so she goes to see Father Meldrum (alone, as you would), where he rather lets the cat out off the bag: "Are you afraid of the man who defiled you? He won't do that again… let me show you the way to true happiness!"

After finding out that Meldrum tapes his confessions and uses them for blackmail, Jenny runs away (again), and is overjoyed (?) to find that her boyfriend's back. He's less than overjoyed, however, to find out about the blackmail: "Bugger the church authorities, I'm gonna sort 'im art meself!"

It's around this point that the body count starts to multiply. First the boyfriend is beaten with an incense burner and then buried alive in a grave, then poor unlucky Bob is smothered in his hospital bed, Meldrum found reading him his last rites after doing the dirty deed. Valerie's mum gets fed a poisoned communion wafer, and another main character gets strangled with rosary beads.

All through the film there are some lovely touches - Sheila Keith is awesome as Meldrum's one-eyed housekeeper, threatening his infirm mother ("He's gone out again, I'm afraid… you're all alone again… with me") and simply raising one eyebrow on surveying the scene following the rosary bead strangulation.

Meldrum's relationship with his mother has echoes of Psycho ("Oh mother… I need your help so badly. The old temptations have returned…") and the scene where mum hands Vanessa a note stating simply "Help me, my son is mad" is enough to bring the house down. And as for that ending…

House Of Mortal Sin marked the end of Pete Walker's trilogy of well-regarded "suburban horrors", made up of House Of Whipcord and Frightmare. It's also of at least equal quality to the other two. But don't let anyone tell you that his magic touch finished with this savage attack on the hypocrisies of the Catholic church - it's worth hunting down his later works (Schizo and The Comeback), as they all display his bizarre, but entertaining, view of post 60s life. Mortal Sin also has probably the darkest ending of the lot. To tell you what it is would spoil the film, but it's a cracker…