It was a triangle that ended with a tragic walk in the woods,

and its small-screen dramatisation, showing on Monday,

proves truth can be more compulsive viewing than fiction

IT would be stretching the imagination to describe Kate Hardie as

classically beautiful. Indeed, there is a distinct possibility that she

looks a little like her father. The problem is that no one really knows

what her father, the former Goodie turned bird-watcher Bill Oddie, looks

like underneath his heavy-duty beard.

But there is an undeniable coquettish charm about razor-haired Hardie,

a combination of innocence and mischief in her face. She appears

vulnerable, impressionable, gullible. She seems to have the word

''victim'' stamped across her forehead.

In her relatively short screen career to date, the 27-year-old actress

has played an abused homeless teenager (in Antonia Bird's award-winning

film Safe), the long-suffering wife of East End mobster Reggie Kray (in

The Krays), and the girlfriend of transvestite psycho David Martin (in

Open Fire).

On Monday her distinguished list of television performances stretches

even further with Beyond Reason, a scorching two-hour drama from

Carlton. She portrays real-life killer Susan Christie, the mistress who

murdered the wife of her Army Captain lover in 1991. So why, as an

actress, does Kate Hardie have this thing about traumatic roles?

''I'm very attracted to heavyweight material,'' she says. ''Actually

having some sort of input into society and showing things as they are

makes acting incredibly interesting to me.

''I'd like to do some lighter work but actually I still find acting a

bit embarrassing as a job for a grown-up, so if I do something that has

a bit more power I feel more responsible.''

Beyond Reason, which cost #1.5m to make, is based on the trial

transcripts of the actual case. It is written by Lucy Gannon (Soldier

Soldier, Peak Practice) and co-stars Simon Shephard (Peak Practice,

Chancer) and Jennifer Ehle (Camomile Lawn). It is a classic case of

truth being far more compulsive viewing than fiction.

On March 27, 1991, two young women, Penny McAllister and Susan

Christie, went for a walk in Drumkeeragh Forest, County Down. Fifteen

minutes later Penny was lying dead, her throat slashed, and Susan was

running from the wood, screaming hysterically.

She claimed that they had been attacked by an unknown man who had

attempted to rape her and slain Penny. Three days later, Susan was

charged with the murder. The police had made the fatal connection. Penny

was the wife of dashing Captain Duncan McAllister, a fast-rising officer

in the Royal Corps of Signals who was on a tour of duty in Northern

Ireland, and Susan, a private in the Ulster Defence Regiment, was his

mistress.

The subsequent and highly-publicised trial ended with Susan being

sentenced to four years in prison; increased to nine years on appeal.

The most compelling aspect of the affair was the fact that it should

have happened the other way around. In crimes of passion it is usually

the mistress who is the victim, not the wife.

The seeds of tragedy had been sown two years earlier when Susan met

the ambitious and determined McAllister at a local diving club. What

happened next was little more than a casual fling to the officer but it

was a torrid and passionate love affair for the young woman.

McAllister may have been an officer but he certainly was no gentleman.

His unbecoming conduct started only two weeks after he met Susan, then

19. It was he who suggested that they become lovers. He would make love

to her on the shores of Belfast Lough and, when his wife was away, in

the bedroom of his married quarters. Once, while on a diving trip

abroad, they made love in the water while the unsuspecting Penny

sunbathed on the beach.

The affair came to a head in 1991 when McAllister told Susan he was

being posted to Germany. It was over. They would, he said, have one

final weekend together. They never did. Three days later, Penny and

Susan went for their fateful walk in the woods.

Susan Christie's five-day trial in Belfast ended with her being found

not guilty of murder but guilty of manslaughter on the grounds of

diminished responsibility.

The case raised questions about the law of homicide, sentencing

policy, military discipline and, ultimately, the human heart and mind.

How could an apparently respectable, well-brought-up young girl take the

life of a beautiful and selfless woman. And, more to the point, how

could she think that she could not only get away with it but also end up

with her victim's husband?

Writer Lucy Gannon explains: ''I gradually became intrigued by this

awful tragedy, by our ability to delude ourselves and to destroy life

for the meanest and shabbiest of reasons.

''I did not go into this project lightly. There is a responsibility to

the memory of Penny and to her family as well as to the family of Susan,

because they too are innocent of wrong doing. There is a duty to the

truth, neither to glamorise it nor to blacken any further the names

involved.''

Kate Hardie describes the film as ''a terrifying modern study of

flawed human beings''.

She goes on: ''I can't understand killing but that's because I'm

squeamish. But I can understand losing perspective and reality and

rationale so much that in a split second you've done something that your

brain is telling you you can't have done.

''I'm sure Susan Christie was an extraordinary, ambitious and

forward-thinking girl and got what she wanted in a tough, male-dominated

aggressive world.''