Irian Jaya - Indonesian New Guinea - is a vast tropical wilderness of glacier-capped mountains, pristine rain forest and lowland swamps, sparsely populated by tribal peoples living much as they have done for thousands of years. It might seem an unlikely place to be taken 'hostage' by 'terrorists', both words being so modern in their connotations, but this is what happened to our group of 12 biologists in January 1996. It goes to show that no corner of the world is so remote and untouched that it can be assumed immune from such threats.

Every country has some form of internal strife, some group that is fighting the state. Even if there is no history of kidnapping, there is no guarantee that one of these groups might not decide to take hostages as part of some crazy new strategy. However, if you are an independent traveller who stays on the beaten track and follows FCO or State Department advice closely, the chances of ending up in shackles are negligible. But those people whose work, study or inquisitive nature takes them to more unusual places must do extra research.

Our group spent two years in preparation. We knew about the existence of the OPM Papuan independence movement and knew that the Indonesian military had committed atrocities in Irian Jaya. The missionaries, mining companies, governments and many other organisations that we consulted suggested there was no risk. It seemed a sensible conclusion. The atrocities were too far in the past, the current trouble spots were too far away from us and the OPM had too few supporters. We were all wrong. Resentment among a people lingers and spreads. The OPM had wide support and although they could not read or write and had only bows and arrows they were still very dangerous. It is essential to understand the history of an area: don't ever underestimate the risks and don't always believe the experts' advice, however much you want to.

When we first arrived by light aircraft at our remote village in the mountains everything seemed peaceful and trouble-free. The village head men greeted us and smiled happily and for two months everything went very well. It is easy to be lulled into a false sense of security, and important to be aware that there may be other factions who see your arrival differently. In our case they numbered 200, were from the next valley and they ambushed us on 8 January 1996. We knew some of them already. Almost all of them were young men about our own age living normal Papuan lives. These are the type of people who make up most guerrilla outfits.

The ambush was a very frightening experience. The crowd had worked themselves into a frenzy and sported painted bodies, head-dresses and machetes. We thought we would be killed, but much of the aggression was theatre and no harm was done to us. When it started to rain the mood seemed to pass, they introduced themselves as OPM rebels and we all went inside and ate lunch together.

At first we were worried that they would abuse the women (men in large phallic penis gourds tend to look quite threatening) but none of the five women was seriously molested. One of the hostages was pregnant, and was greatly respected because they believed pregnant women could cast powerful curses. We made it clear that each woman was married to at least one of the men. We were also very concerned for the Indonesians - the obvious enemies of the Papuans. Thankfully the OPM had accepted that we were all there with good intentions, so we were treated with respect; more like guests than prisoners.

In fact our group was seen as a gift from the Lord. White people are almost revered by the Papuans because of the work of the missionaries. In our case it was naïvely believed that we were so important and powerful that we could be traded for independence - a 'free country'. The unborn child of the pregnant hostage was even perceived as the new Messiah who would lead the Papuans to victory. These interpretations helped to seal our fate. Be aware that other cultures may see things in radically different ways from us. To minimise the effects of this, keep visits short. It takes time for rumour and superstition to spread and even longer for people to act on it.

The first night in the village seemed quite exciting, but it was so bizarre I found it difficult to take seriously. The next morning, however, our captors announced that they were taking us into the forest to hide us, and I suddenly became very frightened. We packed up everything; about half a tonne of the stuff. Much of the useless equipment made good presents for people - even cameras and Walkmans were valued for their shiny components. As we were marched into the jungle I remembered the old army adage that 'the longer you wait the harder it becomes to escape', and began to make many daredevil plans. Thankfully I didn't attempt any, but from then on I always kept a knife, compass, matches and iodine in my pocket - just in case.

At first we were sure it would all be over within days, but we quickly realised the situation was very serious. For a start, they declared that the baby - the new Messiah - had to be born on Papuan soil, and it wasn't due for another six months. Our main fear, though, was that the Indonesian military would come in and bomb the whole place and declare we had been murdered by the rebels. The OPM were as frightened of them as we were. Almost immediately we found we had common ground. The first priority was to get news of our kidnapping to the outside world, so that our embassies could prevent the military from wiping everyone out. As only one or two of the OPM men could read or write, we prepared all the letters for them. They were sent out by runner to the nearest town (about a week away), but finally our short band radio was found and used to negotiate with the missionaries. Thankfully in those first days we were able to communicate a lot of information about our situation. We also became very involved with the negotiations on the OPM's behalf and got quite carried away with our demands, thinking that we could organise both sides into compromising a little. It is tempting to imagine that your situation is a special case: always remember, however, that no respectable authority will openly make concessions to terrorists.

This alliance with our captors ensured they treated us well. Many were very nervous at first and hid this with a false bravado which was fairly easy to break through. I made a concerted effort to joke and laugh with the men, believing they would be less likely to kill me if they liked me. In fact we soon realised that all the OPM actively wanted to be our friends, because it gave them status. We used this to our advantage by giving presents only to those who treated us well or seemed to think we should be released. This created competition and jealousy among the OPM and gave us more power.

While we also wanted the OPM to like us, we had to be careful not to be too compliant. The odd refusal or confrontation made them think twice about asking us to do stupid things. As time went by we made a point of showing our frustration and unhappiness, so that they would not forget that they had taken innocent people prisoners.

Over the four months of our captivity, conditions in the mountainous jungle were harsh. We were moved 28 times; sometimes staying in villages but more often being hidden in remote forest. Although we were never tied up and were able to wander around reasonably freely, there was little chance of escape. Our captors knew we were almost totally dependent on them for food, shelter and direction.

Many of us suffered from malaria, dysentery, tropical ulcers and infections, but we had just enough basic medicines to treat ourselves. Thankfully we suffered no serious accidents and no run-ins with snakes or poisonous spiders. For me, boredom and hunger were the worst things, especially when they were combined. You can only make conversation with your companions for so long. After that it is a matter of reliving old journeys, daydreaming, making plans or playing games - if you can find the material to make dice or a pack of cards. The OPM worked hard to find us what food they could (mainly sweet potatoes), but we soon learned to appreciate anything that moved: frogs, rats, bats, tree kangaroos, weevils. More than once we got food poisoning from meat that was too old.

Food was so limited and we were so hungry that initially this became the cause of all major arguments. After a while we realised that if we could rise above our animal instincts, giving a little extra rather than taking a little extra, the world became a much more pleasant place to be. Despite these conflicts, the entire group became very loyal to one another, like a family. But it was a lonely time. You can't expect to find a soul mate in everyone. In a way this was good because we learned to be strong, independent and self-supporting. This made us better able to take care of each other in a crisis. Images of family and home were very important in battling with depression and despair. Some found solace in fantasy worlds, others in prayer or meditation. Certainly we all rekindled the remnants of any faith we had once had.

The OPM promised many times to release us, but not one promise was kept. There was so much conflicting news that it was tempting to attach too much significance to rumours of release. The disappointments were bitter and it took us several months to realise that the most painless way to get through was to let go of our hopes of release. Once I had resigned myself to being there forever I began to appreciate the present more, taking pleasure in the small things in life such as a beautiful sunrise or a moment of shared laughter. I also gained comfort and enjoyment from simple habits and routines, such as going to wash, collecting water or preparing food. The moment I stopped counting the hours the days seem to pass more quickly. Most important for me was understanding that this captivity wasn't wasted time, but an experience that would make me stronger and become an important part of who I was.

After about two months, the Red Cross made contact. From then on we were able to receive and write letters to our families about once a fortnight. There were also medicines, books and food, but soon the OPM came to enjoy the free presents so much that the Red Cross had to stop bringing in anything. This made the OPM angry but also focused their minds on the negotiations. Finally they agreed to hold a pig feast and release us on 8 May 1996, but at the last minute they refused. Perhaps they thought they should hold out for more. Maybe it was an act of angry defiance. Whatever, the next day we heard helicopters, gunfire and then a series of huge explosions (possibly blanks, but certainly powerful enough to blow down trees and start landslides).

This was the military operation we had dreaded. After an initial period of intense fear and panic we managed to think rationally. We had been told by the Red Cross that if things got nasty we should just lie down. But this was not an option, as we had to get away from the house in case the military bombed it or the hard-line OPM came to get us. We heard about four helicopters circling, trying to find us, but the canopy was too thick. Then we heard a high- pitched whine which I now know was the sound of troopers being winched down into the forest. In hindsight, we should probably have split up and hidden in the forest close by until the military found the house. Instead, we made for a clearing from which we could signal but were intercepted by a group of OPM before we got there. We were taken into the mountains, and for five days the military tracked us with sniffer dogs, a heat- imaging camera mounted on a pilotless drone and trackers who followed our footprints (the Papuans do not wear shoes). On the sixth day, quite unexpectedly and very calmly, our captors attacked us and killed the two Indonesian men. The rest of us were able to get away. We ran down to a river, where we found a small military patrol camped on the bank. The OPM had seen the patrol, realised everything was over and killed the Indonesians to show that they would not be beaten.

We were flown out by helicopter and looked after incredibly well by the Indonesian government and British Embassy, but it was difficult to celebrate with the horror hanging over us. The press followed us everywhere and were such a problem that we decided to do an exclusive for one newspaper so that the others would leave us alone. Although we would have liked to address the political and human rights issues in a broadsheet interview, we were so confused and angry that we felt happier telling our story to a tabloid who would leave these things well alone. We chose the Mail on Sunday, which did one big feature, treated us exceptionally well, reported very accurately and paid us enough to provide some security in the coming months of readjustment.

For a few weeks I found I was very nervous and frightened of simple things such as going outside alone. It was exhausting speaking to friends on the telephone, so everybody wrote instead. We were offered counselling by the Foreign Office, but we needed to arrange it through our GPs and in the end it all seemed too much hassle and none of us bothered. I decided the best therapy was time with my family in Cornwall. Within three weeks I plucked up the courage to go and see friends in Cambridge, and I was amazed at how quickly I was back in the swing of going to pubs and parties. I felt very detached from my experiences in Irian Jaya, perhaps because they seemed so surreal. It might have been easy to pretend the whole thing never happened, but I could feel the experience had changed me and I was not happy having all these subconscious emotions inside me. I decided to write a book, not only for cathartic reasons but also because I felt it was a story that needed to be told.

Writing the book was a gruelling experience which felt a little like a penance, but those six months helped me to come to terms with my anger and guilt. Once the book was finished I found I had little idea of what I wanted to do. But perhaps that is no bad thing. Being taken hostage teaches you that you never know what's around the corner...