Chloe Leach, 21, had drank around four cans of the energy drink and several VKs - a vodka based drink which also contains caffeine - when she suddenly fell to the floor in the Sugarmill club in Hull, East Yorks., on September 30 last year.

Miss Leach, a third-year social work student, of Cottingham, East Yorks., died at the scene despite efforts from staff and paramedics to revive her.

A doctor told the inquest into her death on Monday that it may have been caused by the caffeine triggering a rare heart condition.

It was thought initially that her drink had been spiked but the theory was rebutted by a medical expert at the hearing.

Miss Leach, who had been diagnosed with epilepsy in 2001 after suffering fits and seizures, was believed to have QT Syndrome - a condition which affects the electric activity in the heart.

She also had an abnormally large heart, and the doctor who carried out the post-mortem felt it was "probable" that the caffeine had raised her QT Syndrome level to "abnormal".

Dr Ian Scott, a consultant neuropathologist, said: "On the basis of probability, her epilepsy, the QT, her abnormal heart and the the high levels of caffeine found, the most likely cause of death was a cardiac arrhythmia due to underlying QT Syndrome.

"I excluded drugs as a cause - the only drugs she had taken was her anti-epilepsy medication. QT sufferers are prone to sudden arrests, the threat of which may not be detected during normal scans."

Miss Leach's mum Tina had suffered a heart attack some time ago and her cousin had previously died suddenly, which meant her entire family were scanned to search for defects, the hearing was told.

Although she was never officially diagnosed with the syndrome, she had a QT "upper limit" which Dr Scott added could have increased in the years following her scans.

He said: "The QT levels may have grown over a few years, or it may have been artificially pushed over the limit by caffeine."

In the early hours of the club's student night, just before Miss Leach collapsed at around 3am, guest DJ Danny Latimer was hospitalised claiming his drink had been spiked, leading to rumours that she had been the victim of a similar crime.

But it emerged that the former 'Shipwrecked' star had been charged with possessing Class C drugs and perverting the course of justice, and any link between the two incidents was dismissed. A medical report confirmed that Miss Leach had no drugs in her system other than her anti-epilepsy medication.

Miss Leach's mum Tina, giving evidence, said: "Chloe was careful regarding her consumption of caffeine. She would drink Red Bull occasionally and was aware it contained caffeine.

"My concern is that we will never ever be able to prove she had QT Syndrome. We will always doubt the circumstances surrounding Chloe that night. I accept that we don't have any evidence she had any substance in her *lo**, but the description we have of what happened to the DJ is so similar to what happened to her.

"It seems too much of a coincidence and there are so many things that don't add up."