Missing. Dinah's file is still open

Eleven years ago this summer Dinah McNichol, a bright 18-year-old, said goodbye to her father, Sam, and her brother and sisters, Sarah, Daniel and Shona, and set off to celebrate the end of her A-levels with three schoolfriends.

Like thousands of teenagers who now go off on gap years, she'd been working hard and applying for university courses. Her father remembers taking her down to Brighton from their home in Tillingham, Essex, for an interview at Sussex University.

"I felt she'd really deserved a break after all the work she'd done," he says. But he never saw her again. Dinah and her friends were off to an illegal pop festival on MoD land at Liphook, Hants. And that wasn't all. She said she might travel on to another festival with her friends after that.

"I told her to give me a ring," says Sam, but, knowing she was with friends and thinking that she might have gone on to another festival or to stay with relatives in Lincolnshire, he didn't worry too much when she didn't.

"I got a phone call from her older sister asking if I had heard from her," he continues. "I rang her nan in Skegness and she hadn't heard from her and that was when I rang the police."

Sam McNichol and his family have been waiting for a call ever since because Dinah, who would be 29 by now, is a registered missing person, someone of whom no news has ever been heard, and her disappearance has left her family in a state of suspended emotion and uncertainty that has tormented them ever since. Sam himself has been profoundly affected. He's had a heart attack and two strokes, but he keeps talking just in case, one day, someone might know something or his daughter might return.

"Whenever a child goes missing, whenever this comes up on the television, I think, oh my God, I really feel for the parents because I know what they're going through. Nobody else does. Whenever anyone tells me, I know what you're going through, I say, no you don't. You can't, unless it's happened to you. It shouldn't happen to anyone."

Sam McNichol knows from first-hand experience that having a loved one disappear is worse than death. He knows because he had to identify his wife's body when she was killed in a car crash when Dinah was six years old. She was killed in a headlong collision with a man who was overtaking a motorbike and hit her head-on.

"Our son, Daniel, was in the back of the car and there were toolboxes in the boot which apparently shifted and protected him from the impact. They saved his life but his legs were damaged. They gave him 48 hours to live but he recovered, though he still has problems walking.

"My wife was only 39. It's terrible, but you can actually grieve. If someone goes missing and isn't found there is no way of grieving. You can't grieve unless you know what's happened."

Sam McNichol had come down to the south from Glasgow as a jazz musician playing the banjo in Dixieland bands, a precarious living, so he was working on a local chicken farm in Essex to bring in money for the family. Suddenly he found himself the sole parent to his stepdaughter Sarah, then 15, and the three younger children.

"It was all made even more difficult by the local social services, who said that a man couldn't bring children up on his own," said Sam. "That was how they thought back then. They wanted to split the children up, but a friend told them that if they took my children away it would finish me, so I managed to hang on to them. Sarah went back to her real dad, a teacher, because she was very brainy and I could see that if she stayed she was going to turn into a mum for the little ones, which wouldn't have been fair. She's a teacher now."

As a widower with three young children Sam was giving all his attention to bringing them up, so he lost his job on the chicken farm and devoted himself to staying at home and taking care of the children. Daniel and Shona went to boarding school nearby, but Dinah, who was very bright, was sent to the local county high school at Chelmsford. Her trip to the pop festival was, apart from a school trip to Venice, her first real stay away from home.

"According to her friends she'd met a bloke there and they got together. The police came round - in fact the main detective on the case got commended for his work even though he never found her. He went everywhere. At one point they did a search in Hampshire and I went down there - that panicked me - there were hundreds of police. There were police there with children the same age who'd come in on their own time.

"But they found nothing. It seems that Dinah had arranged to meet the boy again, and he was found, but in the meantime, another man, who has never been found, offered her a lift home to Essex so that she could collect some clothes and some money. She had £2,000 in the bank saved for a holiday. She never arrived home and the man and his car were never seen again, but over the next few days somebody used her bank card to draw £200 out of a different cash machine each day along the South Coast, taking care to leave just enough money in to avoid alerting the bank."

Sam was shocked to find that even he was under suspicion: "The police came round and took statements. They went up to Skegness to talk to her grandparents, they interviewed all her friends, all my family. They asked me if we had any problems with her at home, but we hadn't. They went up in the loft, they searched the garden. I couldn't believe it, but they told me most people who go missing are found around the house or the garden. I just watched them in utter disbelief."

SAM was eager to try anything that would find his daughter, so he made media appeals. Dinah's story was the first missing-person appeal to be on Crimewatch UK and that produced more than 400 responses, but none of them led anywhere. Slowly the search died down and the McNichol family was alone again.

"The children were the same as me; it's not easy. It didn't do my health any good. I've had one heart attack and two strokes. They asked if I would like to see a counsellor and I said no, but I think I should have. But I was brought up that way: I'm a stubborn Scotsman.

"I started my working life in the same Glasgow shipyards as Billy Connolly. You just don't talk about these things. I used to get very depressed about it, really, really depressed, but that wasn't doing any good, so I'd try to block it. I used Valium and booze, but it takes

longer to come to some semblance of terms, doing it on your own.

"Dinah had shared a room with Shona, and one of the good things about Shona going to boarding school is that the staff were absolutely brilliant, they'd talk to her when she got depressed. Shona works in a chemist's shop now. And Daniel's done well. He's married to a really nice girl and he has a good job with an employment agency."

Which leaves Sam. The only time he feels he's with people who understand is when, on his rounds of talk shows and interviews, he meets other parents whose children have disappeared. It's an exclusive but desperate club and you can never resign.

"It's still unreal. It's still the sort of thing that happens to other people, not you. It's had a sobering effect on the children, but they're young. I never get over it. I still think of her, and every time I watch a programme about missing children or something happens, like that schoolgirl Milly missing in Walton-on-Thames, I feel for the family. I would say to them, talk to someone, to someone who understands because they've been there."

As for Dinah she is still a ghostly presence in the family, someone whose name suddenly slips into the conversation, someone who's not quite gone away, but Sam McNichol says it's easier to have memories of the dead than someone who's vanished. The feeling is not gratitude for warm memories, but a sense of despair that they should ever have been robbed of them. Dinah's file is still open.