Christopher Hirst: No mystery but plenty of intrigue

David Suchet played Poirot with a twinkle in his eye and a pertness to his waxed moustache

The news that Julian Fellowes and Neil LaBute have formed an unlikely alliance to make a film adaptation of the Agatha Christie yarn Crooked House comes as a semi-surprise. Not so much for the involvement of Julian Fellowes, who staked a proprietorial claim to dark doings among the upper orders and their servants with his script for the movie Gosford Park. His exploitation of this rich vein later produced the hugely successful TV series Downton Abbey. Official recognition of his role as the leading dissector of the class system came with his elevation to Baron Fellowes of West Stafford in the New Year Honours.

Neil LaBute is, however, an entirely different kettle of fish. Born in Detroit, this former Mormon has been called "American theatre's reigning misanthrope". He is renowned for chilling and, some would claim, bracing dramas that explore dark and dangerous characters. His early success In the Company of Men concerned a plan by two vicious executives to woo and subjugate a deaf woman. A trio of short plays ripped apart the bland, no-coffee-for-me-please innocuousness of the Mormons. The Mercy Seat from 2002 concerned a worker in the World Trade Centre who, having escaped the attack because he was on the job with his mistress, sees the possibility of utilising the disaster to start a new life.

These murky themes seem a world away from Christie's whodunnits with their cut-out characters, unfeasibly brilliant investigators and curiously anodyne violence. As a devotee of Christie re-runs on ITV3, I have become something of an expert on her oeuvre. I suspect the same applies (judging by the adverts for chocolate and detergents) to a large part of the UK's female population. You know that the blood is the stage variety known as Kensington Gore. It is obvious that the deceased will spring to life Lazarus-style as soon as the camera stops rolling and enjoy a reviving cup of tea.

At least, this was the case with the early adaptations of Poirot. David Suchet played the Belgian sleuth with a twinkle in his eye and a pertness to his waxed moustache. Joshing with his dull but amiable sidekick Hastings, he ran rings round the dogged, ever-gabardined Inspector Japp. Each episode would end with the murderer dragged away kicking and screaming ("I'll get even with you, you foreign meddler!") while the three protagonists enjoyed a little plaisanterie by way of a pay-off.

But as the budget and length of the episodes increased, the cheery associates were dropped and the character of Poirot darkened. In the latest film, a chilly and decidedly violent version of Murder on the Orient Express, the detective ended up in tears, grasping his rosary for solace, as he condemned the participants in an apparently justifiable homicide to the course of the law.

As with adaptations of Sherlock Holmes and James Bond, even the tea-and-crumpets world of Agatha Christie can change with the mood of the times. Because they are indifferent to subtleties of character, her cleverly constructed yarns can be retold in a host of ways. These efficient but undemanding narratives act as canvas designs that directors and actors can imaginatively embroider. This will not have escaped the attention of Messrs Fellowes and LaBute. More to the point, they will be assured of an audience. Christie remains box-office gold.

Lacking the reassuring presence of Poirot or Marple, Crooked House is a relatively unknown corner of the vast Christie terrain. Yet she maintained it was one of her two favourite works. Let's take a little peep inside. Following the mysterious death of an Anglo-Greek millionaire, poisoned by eye medicine, his granddaughter Sophia cannot marry until his killer is nabbed. Her fiancé, Charles, decides to investigate the case with his father, who happens to be a commissioner at Scotland Yard. The entire family are suspects but it emerges that Sophia is the sole legatee ... Hooked? You will be.