More than a decade and a half after her brutal murder, Sarah Payne's three siblings have spoken of how her death impacted on them.

Sarah was eight-years-old when she was murdered by paedophile Roy Whiting on July 1, 2000. Now a new Channel 5 documentary sees her immediate family speak publicly for the first time of her tragic death. Luke was just 12 when he was out with his brother, Lee, and sisters Charlotte, as well as little Sarah. He describes in the documentary how Sarah ran ahead of them and dipped through a gap leading to a road on the edge of a field in Kingston Gorse, West Sussex. She was never seen alive again. Sarah had been snatched by Whiting, who is currently serving life imprisonment for her murder; he smiled and waved at her siblings as he drove away in his van with his young victim in the back.

Luke is understandably deeply traumatised by his harrowing experiences.

"I'm scared to sleep half the time so I work myself solid until I pretty much drop," he tells Channel 5, adding "Because it's fears of what's there when I close my eyes.

He goes on to say: "I always think about what she'd be like now, I see her friends about - some of them have got kids, others are working, one just got married - I always wonder what she would be doing."

Sarah's father, Michael, died in 2014, but the rest of her immediate family - including her mother, Sara - take part in the documentary. During the same screening, eldest brother Lee admits: "When it comes to feeling guilt about the situation, I did for a few years beat myself up… that if I ran faster… I might have caught up with her."

And her sister, Charlotte, who was just five at the time of Sarah's disappearance and death, says she has often asked: "Why was it her and not me?"

Sarah's body was found two weeks after the day that Whiting took her. He is not eligible for parole until 2051. Sarah Payne; A Mother’s Story, Wednesday 19 July, 9pm on Channel 5