'I will be all right up there,' she said, pointing towards the rig. 'I will wait here until it comes.'

In the car Dr Marriot was already sagging into sleep.

'Hop in, Dan. We'll move on slowly. At least moving creates a draught,' I said. The crawling pace was more frustrating than ever but I had to content myself with the thought that Captain Sadiq was coping very efficiently, better than I had done, and that in Dr Margretta Marriot we had a very useful addition to our staff. The Wyvern Travelling Hospital ground on through the hot African day. The sooner we got to Kanja, the better.

Half an hour later the whole pattern changed again. We seemed to be living inside a kaleidoscope which was being shaken by some gigantic hand. A motorcyclist, one of Sadiq's outflankers, roared up and said that Captain Sadiq would like to see me. I pulled out of line hoping not to disturb Dr Marriot, though I doubted if anything short of an earthquake would waken her.

Kemp and Wingstead were already with Sadiq, talking to two white men, more strangers. Behind them was a big dreamboat of an American car which looked as out of place in that setting as an aircraft carrier would on Lake Geneva. Atheridge and I got out and joined them.

One of the men was tall, loose-limbed and rangy, wearing denim Levis and a sweat-stained checked shirt, and unbelievably he was crowned by a ten-gallon hat pushed well back on his head. I looked at his feet; no spurs, but he did wear hand-stitched high heeled boots. He looked like Clint Eastwood. I expected him to produce a pack of Marlboros or a sack of Bull Durham tobacco.

By comparison the other guy was conventional. He was shorter, broad-shouldered and paunchy, and dressed in a manner more suitable for Africa; khaki pants and a bush jacket. Both looked dusty and weary, the norm for all of us.

I said, 'Hello there. Where did you spring from?'

The tall man turned round. 'Oh, hi. Up the road a way. You folks got the same trouble we have.'

Kemp's face was more strained than usual.

'Neil, there's a bridge down further along the road.'

'Christ! The one you were worried about, way back?'

Kemp nodded. 'Yes. It's completely gone, they've just told us. It spans a ravine. And it's this side of Kanja. It would be.'

Wingstead looked more alert than worried, ready to hurl himself at the next challenge. He was a hard man to faze.

I said, 'I'm Neil Mannix, British Electric. I guess it's a pleasure to meet you, but I'm not sure yet.'

The tall man laughed. 'Likewise. I'm Russ Burns and this is Harry Zimmerman. We're both with Lat-Am Oil. There are some other guys up the road too, by the way – not our lot; a Frenchman and a couple of Russki truckers.'

'What happened? Did you see the bridge go down?'

Burns shook his head. 'We were halfway to the bridge when the planes hit Kodowa. Mind you, we didn't know for sure what the hell was happening but we could guess. We'd seen a lot of troop movement a few days before, and there were stories going round about a rebellion. We couldn't see the town itself but we heard the bombing and saw the smoke. Then we saw the planes going over.'

His hand went to his shirt pocket. 'We didn't know what to do, Harry and me. Decided to push on because we didn't fancy turning back into all that, whatever it was. Then we met up with the Russkies.'

'A convoy, like ours?' I watched with fascination as he took out a pack of cigarettes. By God, they were Marlboros. He even lit one the way they do in the ads, with a long, appreciative draw on the first smoke. He didn't hand them round.

'No, just one big truck. The Frenchman's driving a truck too. He had a buddy he'd dropped off in Kodowa. I guess he must have got caught in the raid. You didn't see him?'

Nobody had. Write off one French trucker, just like that.

'I was shoving my foot through the floorboards the first ten miles after that raid,' Burns said, 'Even though I knew we couldn't outrun a jet. Maybe thirty miles from here we turned a corner and damn near ran into this pipe truck. The Soviets. They hadn't seen or heard anything. Then the Frog guy turned up, him and a nig… a Nyalan assistant.' He glanced at Sadiq as he said this.

Zimmerman spoke for the first time. 'We four camped together that night, and the next day we pushed on in our car with one of the Russians. I speak Russian a little.' He said this almost apologetically. 'Ten miles on there's this bridge.'

'Was this bridge. By God, it's just rubble at the bottom of that ravine now. Took a real hammering.'

'Was it bombed?' I asked.

'Yeah, I reckon so. We could see the wreckage, five hundred feet down the hillside.'

'Any chance of getting across?' I asked, even though I could already guess the answer.

'No chance. Not for a truck. Not for a one-wheel circus bicycle. There's a gap of more than two hundred feet.'

Burns inhaled deeply. 'We all just stuck around that day. Nobody wanted to make a decision. Our radios only picked up garbage. We couldn't go on, and we didn't feel like coming back into the middle of a shooting war. The Soviets had quite a store of food and the Frenchie had some too. All we had to put in the pool was some beer, and that didn't last long, believe me. Then this morning we decided we'd go two ways; the Frenchie was to have a try at Kodowa with the two Reds, and Harry and me said we'd have a go at getting through the gorge on foot and make for Kanja.'

'Can't say I was hankering for the experience,' put in Harry.

Then just as we were about to get going, up comes these two guys.' Burns indicated Sadiq's riders. 'We thought at first the rebels had caught up with us. Hell of a note, and us with just a couple of popguns between us. Then they told us what was going on back here. It didn't sound real, you know that?'

I made mental note. They had weapons.

Travelling circus,' Kemp muttered.

'Wish it was, buddy. Elephants now, they'd be some use.

Anyway, we changed our plans, left the truckers to wait up ahead, and Harry and me came back to see for ourselves.'

I asked, 'Is it possible to cross on foot?'

'I reckon so, if you're agile.'

I looked at Sadiq. 'So?'

Wingstead said, 'What's the use, Neil? We can't send the wounded and sick that way and even if the Kanja hospital is still in business they can't send help to us. You know what we have to do.'

I nodded. One problem out of a thousand raised its head.

'Basil,' I said, 'how do you turn your rig around?'

'We don't need to,' Kemp said. 'It'll go either way. We just recouple the tractors.' His mind was shifting up through the gears and his face looked less strained as he started calculating. There was nothing better for Basil Kemp than giving him a set of solid logistics to chew on.

Sadiq said, 'What will you do now, Mister Mannix?' He too looked as though the ground had been pulled from under his feet.

I studied our two new arrivals. 'What we're going to do first is get these two gentlemen a beer and a meal apiece. And we have a lady who joined us recently who'd also be glad of something to eat. Geoff, could you get Bishop to organize that? As long as the convoy's stopped, we may as well all stoke up. We'll have a conference afterwards. Captain Sadiq, could you pass the word around that we are no longer going towards Kanja? Everyone must rest, eat if they can, and then be ready to move.'

Wingstead said, 'Who's the lady?'

'She's a medical doctor. She was widowed in the raid on Kodowa, and right now she's asleep in my car. I'm going to have a word with Doctor Kat and I'll take her along. As a matter of fact, Dan knows her quite well…'

I tailed off. Behind us, standing quietly, Dan Atheridge looked pasty grey over his tan. During our briefing from the Lat-Am men Atheridge had been listening and their news touched him more closely than any of us. His wife was waiting for him, somewhere beyond Kanja. He was cut off from his home.