Doctors have pronounced Allison Burchell dead three times.

A rare medical condition, called narcolepsy, means she is overcome by irresistible urges to fall asleep. She then loses control of her muscles and to all appearances is no longer alive.

The 65-year-old Sussex woman's tale of life and death has now been featured in Channel Five documentary Premature Burial.

It was in 1995 when Allison, who grew up in Horsham, was first pronounced dead at the age of 17.

An usherette found her, apparently unconscious, in a cinema after she had slumped to the floor.

The last thing Allison could remember was laughing at her favourite comedy act, Abbott and Costello, but then she found she couldn't move even though she could still hear the film and the giggles from the audience.

She was taken from the cinema, but was fully conscious while nurses, believing her to be dead, prepared her body for the mortuary.

She could hear the medical staff chatting as they worked but was unable to let them know she was not dead.

She said: "They had no idea I could hear everything they were saying. I was paralysed, but in my head I was calling them all the names under the sun. I was petrified."

Allison was taken to the mortuary where she eventually came round.

She said: "There were all these corpses around me and I just didn't know what to do.

"I just sat there and then the attendant came in and I think he got an even bigger shock than I did."

Months of tests followed and Allison was finally diagnosed as suffering severe narcolepsy, which has symptoms including an irresistible urge to fall asleep and cataplexy, which leads to sudden loss of control over muscles.

Cataleptic fits are triggered by periods of extreme emotion including laughter, anger, excitement and fear.

A few years after her diagnosis, Allison suffered another attack and was taken to a mortuary after being pronounced dead for the second time.

Allison, who is now married with four children, said: "When the doors closed it felt like being in a tomb.

"It dawned on me that someone had to die before they'd open the doors so I was wishing it to happen."

She suffered her third attack in the Seventies, after she had moved to Melbourne, Australia.

Allison's 15-year-old son, Stephen, begged paramedics not to put his mum in an airtight fridge unit after she had collapsed at home because he knew that really would kill her.

Allison said: "I was so worried because in Australia, they don't just put you in a cold unit and I knew I'd freeze to death."

Medical staff eventually took heed of her son's fears and Allison was put in a side ward where she eventually came round.

Allison said: "You can see and hear everything going on around you but there is no way to convey to anyone that you are not dead.

"It is the most terrifying thing imaginable."

The Narcolepsy Association UK (UKAN), which offers help and support to sufferers, says cataleptic attacks can last a few minutes or up to half-an-hour at most.

The symptoms range from dropping of the jaw to total collapse, but the sufferer continues to breathe and the heart does not stop beating.

A spokesman at the Sleep Disorder Centre at St Thomas' Hospital in London, which regularly deals with sufferers of narcolepsy and cataplexy, said Allison's condition was extremely rare in its severity.

It is estimated about 25,000 people suffer from narcolepsy in the UK with 500 cases being diagnosed a year.

Peter Saunders, of Kent-based UKAN, who has suffered from narcolepsy for 50 years, said he had never dealt with any cases of sufferers being pronounced dead.

But he said it would not be impossible, in severe cases, for narcoleptics to fall into a coma-like state.

He said: "I have heard cases reported but they are extremely rare. We shouldn't forget doctors can make mistakes."

The documentary features several casualties of near-burial experiences.

Maureen Jones, 65, a widow, was saved by a policeman who saw her leg twitch moments before she was to be placed in a coffin.

She collapsed while getting ready for bed and was pronounced dead by a doctor.

While her family waited for a hearse, PC Phillip Shrimpton noticed her leg twitching. He gave her a heart massage and mouth-to-mouth resuscitation.

She was taken to hospital and regained consciousness two days later from what was believed to be a diabetic coma.