Tax collector turned actress Gemma Rigg is to play the harrowing role of the rape victim

in the notorious A6 murder.

Controversy has raged for 40 years over the hanging, in April 1962, of James Hanratty after his conviction of murdering civil servant Michael Gregsten and raping his lover, Valerie Storie, before leaving her for dead.

Gemma, whose family home is in Shoreham, will play the young Valerie Storie in Hanratty: The Whole Truth, to be screened on Channel 4 at 9pm tomorrow.

The programme will feature the first television interview with Miss Storie, who was 22 when she and her married 36-year-old lover were attacked in August 1961 as they sat in a car in a cornfield at Dorney Reach, Buckinghamshire.

Hanratty, 25, was alleged to have forced them to drive to a lay-by off the A6 at Deadman's Hill, south of Bedford, and to have shot Gregsten twice in front of Miss Storie, who was raped and shot five times.

Gemma, 29, who lives in London but grew up in Mill Lane, Shoreham, was offered an audition for the part after producers spotted her photograph in actors' journal Spotlight.

She said: "They wanted someone who had a resemblance to Valerie Storie and they said I did."

The former pupil of King's Manor School, Kingston Lane, Shoreham, added: "The filming didn't go into graphic detail. It was all very subtle but still harrowing."

Gemma has made other TV appearances on EastEnders and Alexei Sayle's Merry Go Round as well as a variety of theatre productions.

She has also written a television sketch show now being considered by Talkback Productions, creators of Smack The Pony and Da Ali G Show.

She said: "I left school at 16 and worked as a tax collector for five years before I ran away to London to go to drama school."

Gemma's mother, Maureen Sheppard, said: "We're very proud of her. She's come a long way since working as a tax officer."

Miss Storie has continued to stand by her "total and absolute belief" that Hanratty was guilty.

But following decades of doubt over the safety of the conviction, the Court of Appeal is now considering whether Hanratty was the guilty man.