The last time I 'died' was in Jerusalem in 1276. Pope Gregory X's Crusade against Islam had collapsed and the city's Christians would soon be abandoned to their fate.

My final hours were filled with fear. I was besieged in a beautiful vaulted church along with 100 knights. Smoky candlelight glinted off their armour. Some knights were praying, others resting.

As dawn broke, they readied themselves for the final conflict with an implacable foe. Even the most devout were terrified. All knew that only a handful would survive the coming day.

I watched their preparations for battle. The sharpening of swords and lances. The reinforcing of shields and armour.

But most of all, I prepared for my own death. As a monk in a city of Muslims, my chances of surviving the coming assault were slim. Soon after the knights left the church, I retreated to a small side-chapel to pray. I was desperate for forgiveness.

I had travelled from a monastery in Kent to the Holy Land so that I could kill Muslims.

Although I still hated Islam, I found it hard to love my own side. The decadence and corruption of the Crusaders had sickened me. I wanted to be left alone to live in peace, but it was too late.

With no knights left to protect me, the rampaging enemy had set fire to the chapel. I watched as the flames roared up the sides of the building.

Soon I too was on fire and burning like a Roman candle. I didn't feel any pain - I knew I was going to die and that my Lord would make it swift.

Out of the blackness I could see a burning white light. A calm voice asked me what I had learned from my life and whether there was any knowledge I wished to carry to the next.

It was the voice of David Wells - a past-life regression therapist who had put me in a trance and guided me to my 'past incarnation'.

To many, the idea of reincarnation will seem like bunkum. But strange as it may seem, it is garnering a surprising degree of respectable scientific support.

Today, London hosts an international conference on the subject in memory of the late Dr Ian Stevenson, an American scientist who spent decades studying the phenomenon.

Dr Stevenson amassed an astonishing amount of evidence for reincarnation. He tracked down more than 3,000 children who claimed to have experienced a 'previous life'.

Many were able to give precise details, such as their former names and the manner of their deaths. They could even recall the names of friends and family, many of whom Dr Stevenson was able to track down through birth records. Others knew intimate details known only to the deceased's family.

Such findings have led respected academics to startling conclusions. 'Reincarnation is the most likely explanation for the strongest cases,' says Dr Jim Tucker, medical director of the Child and Family Psychiatric Clinic at the University of Virginia in the U.S.

'The evidence points to a "carry over" of memories and emotions from one life to another. That could be termed reincarnation.'

Reincarnation is highly controversial - not just among scientists, but between different religions too. Broadly speaking, Christians, Muslims and Jews do not believe in it, while Hindus and Buddhists do.

To most in the West, it is still seen as little more than the product of a far-fetched imagination. But given the growing interest of the scientific community, I decided to investigate whether there could be more to it.

I volunteered to undergo what's known as 'past-life regression therapy'. Practitioners of this discipline claim we have all lived before and that we can be taught to remember our former incarnations.

It sounded utterly preposterous. Yet I must admit to a certain uneasiness, also. What if I were to remember that I had been a murderer or a rapist in a former life? Or, Heaven forbid, one of Hitler or Stalin's henchmen?

Whatever the truth behind it, past-life regression is not without risks. The psychological shock of 'recovering a memory' from a former life can overwhelm some. Others feel guilty about misdeeds 'they' perpetrated.

I took comfort from the fact that David Wells, one of Britain's most experienced practitioners and author of Past, Present And Future: What Your Past Lives Tell You About Yourself, had agreed to be my guide.

I was led into a darkened room and coaxed into relaxing on a big, soft chair surrounded by burning incense and scented candles.