The first thing we saw in the customs but was a picture which gave us a clue about how our expedition to find endangered wildlife in Zaire was going to go. It was a portrait of a leopard. That is it was a portrait of part of a leopard. The part of the leopard in question had been fashioned into a rather natty leopardskin pillbox hat which adorned the head of Marshal Mobuto Sese Seko Kuku Ngbendu Wa Za Banga, the President of the Republic of Zaire, who gazed down on us with a magisterial calm while his officials got to work on us.

One was a large and fairly friendly man who occasionally offered us cigarettes and the other was a small, nasty man who kept on stealing ours. This is, of course, the classic interrogation method, designed to bring the victim to the brink of pathetic emotional breakdown. It's obviously a technique they learnt somewhere and have just found the habit hard to break, even though all they actually wanted to know from us was our names, passport numbers and the serial numbers of every single piece of equipment we had with us.

The big man in particular seemed to wish us no personal ill as he guided us gently through the insanity to which it was his duty to subject us, and I came to recognise a feeling I've heard described when oddly close and touching relationships develop between torturers and their victims or kidnappers and their hostages. There is a feeling of all being in this together. The forms we had to fill in were headed 'Belgian Congo', crossed out, with 'Zaire' written in in pencil, which meant that they had to be at least eighteen years old. The only form they didn't seem to have was the only one we actually wanted. We had been warned by friends that we had to get ourselves a currency declaration form when we entered Zaire or we would hit trouble later on. We repeatedly asked for one, but they said they had run out. They said we could get one in Goma and that would be all right.

They toyed with the idea of confiscating my Cambridge Z88 laptop computer just in case we were planning to overthrow the government with it, but in the end the small nasty man merely confiscated Chris's car magazine on the grounds that he liked cars and then, for now, we were free.

We went into the town of Bukavu in a sort of taxi-like thing. The town turned out to be an enormous distance from the airport, probably at the insistence of the taxi-drivers. As we bounded along the appallingly rutted road that followed the margin of the lake and along which a significant proportion of the population of Zaire seemed to be walking, our driver kept on diving beneath the dashboard of the car for long periods at a time. I watched this with some alarm, which was severely increased when I eventually worked out what he was doing. He was operating the clutch by hand. I wondered whether to mention this to the others but decided that, no, it would only worry them. Mark later mentioned that we had not passed any other motor vehicles at all on the drive, except for a couple of trucks which had been parked for so long that they no longer had any rear axles. I didn't notice this myself, because once I had identified what the driver was doing with the clutch I simply kept my eyes closed for the remainder of the journey.

When at last we arrived at the hotel, which was surprisingly airy and spacious for such a dilapidated town as Bukavu was, we were rattled and exhausted and we started to yawn at each other a lot. This was a kind of unspoken code for being fed up with the sight of one another despite the fact that it was only six in the evening. We each went off to our respective rooms and sat in our separate heaps.

I sat by the window and watched as the sun began to go down over the lake, the name of which I couldn't remember because all the maps were in Mark's room. From this vantage point, Bukavu looked quite idyllic, situated on a peninsula which jutted into the lake. Lake Kivu. I remembered the name now. I was still feeling very jangled and jittery and decided that staring at the lake a bit might help.

It was placid and silvery, shading to grey in the distance where it met the fading shapes of the hills that surrounded it. That helped.

The early evening light cast long shadows over the old Belgian colonial houses that were stepped down the hill from the hotel, huddled about with bright blossoms and palm trees. That was good too. Even the green corrugated roofs of the cruder new buildings were soothed by the light. I watched the black kites wheeling out over the water and found that I was calming down. I got up and started to unpack the things I needed for the night and at last a wonderful sense of peace and well-being settled on me, disturbed only by the sudden realisation that I had once again left my toothpaste in last night's hotel. And my writing paper. And my cigarette lighter. I decided it was time to explore the town.

The main street was a grim hill, wide, dishevelled and strewn with rubbish. The shops were for the most part concrete and dingy, and because Zaire is an ex-Belgian colony every other shop is a pharmacie, just like in Belgium and France, except that none of them, as it happened, sold toothpaste, which bewildered me.

Most of the other shops were in fact impossible to identify. When a shop appeared to sell a mixture of ghetto blasters, socks, soap and chickens, it didn't seem unreasonable to go in and ask if they'd got any toothpaste or paper stuck away on one of their shelves as well, but they looked at me as if I was completely mad. Couldn't I see that this was a ghetto blaster, socks, soap and chicken shop? Eventually, after trailing up and down the street for half a mile in either direction I found both of them at a tiny street stall which also turned out to sell biros, airmail envelopes and cigarette lighters, and in fact seemed to be so peculiarly attuned to my needs that I was tempted to ask if they had a copy of New Scientist as well.

I then realised that most of the essentials of life were available out on the street. Photocopying, for example. Here and there along the street were rickety trestle tables with big old photocopiers on them, and I had once or twice been hailed by a street hustler and asked if I wanted to have something photocopied or sleep with his sister. I returned to the hotel, wrote some notes on the writing paper, which for some reason was pink, and slept as if I were dead.

The following morning we flew to the town of Goma. Here we discovered that even when making internal flights in Zaire you still had to go through the full rigmarole of immigration and customs controls all over again. We were held under armed guard while a large and thuggish airport official interrogated us in his office as to why we hadn't acquired any currency declaration forms at Bukavu.

The fact that they hadn't had any currency declaration forms to give us at Bukavu cut no ice with him.

`Fifty dollars,' he said.

His office was large and bare and contained just one small desk with two sheets of paper in a drawer. He leant back and stared at the ceiling, which had obviously seen a lot of this sort of thing going on. Then he leant forward again and pulled the palms of his hands slowly down over his face as if he were trying to peel it off. He said again, `Fifty dollars. Each,' and then stared idly at the corner of his desk and rolled a pencil slowly in his fingers. We were subjected to an hour of this before he finally tired of our appalling French and let us go.

We emerged blinking from the airport and, miraculously, met up with the driver that some friends of Mark's had organised to take us up into the Virunga volcanoes where the mountain gorillas lived.

The gorillas were not the animals we had come to Zaire to look for. It is very hard, however, to come all the way to Zaire and not go and see them. I was going to say that this is because they are our closest living relatives, but I'm not sure that that's an appropriate reason. Generally, in my experience, when you visit a country in which you have any relatives living there's a tendency to want to lie low and hope they don't find out you're in town. At least with the gorillas you know that there's no danger of having to go out to dinner with them and catch up on several million years of family history, so you can visit them with impunity. They are, of course, only collateral relatives - nth cousins, n times removed. We are both descended from a common ancestor, who is, sadly, no longer with us, and who has, since Darwin's day, been the subject of endless speculation as to what manner of creature he/she was.