Twinkle, Twinkle, Little Spy

not be so assiduously reported.

'Go slow,' ordered Mann. 'His tyres are the same as ours.'

'Less worn,' said Percy. 'And there is one that looks brand new.'

'Well, I don't want to be crawling round in the sunshine, examining tyre tracks with my vest-pocket microscope,' said Mann.

'Do you have a microscope,' said Percy. 'Some of these desert flowers are worth looking at under a glass.' There was no telling how much of it was serious and how much was mockery.

We left the flat hard ground, which the road-builders had chosen, and the going changed to the gravelly surface of the 'reg' and then to rough 'washboard', which made the suspension judder. Percy accelerated until he found the speed at which the corrugations seemed to smooth out, and we made good speed for over an hour until we encountered the first patches of soft sand. Percy sped through them to begin with, and each time found some hard surface before getting bogged down; but our luck couldn't last for ever, and eventually he had to engage the four-wheel drive and crawl to safety.

The going became softer and softer until we were threading our way through a series of dunes. The tracks skirted the higher sandhills, but even so the Landrover was careering about like a roller-coaster ride. The prevailing east wind made the upward side of each dune a gentle slope but the far side was sometimes precipitous. Yet there was no alternative to accelerating over the brink. No one spoke, but it was becoming obvious that only a marginal difference of sand, or a momentary carelessness on Percy's part, would leave us stuck at either the top or the bottom of one of these dunes. We had surmounted one of the gentlest slopes as I heard the sand jamming against the underside of the Landrover and then Percy wrenched at the steering so that we slithered to the valley of the dune in a sideslip that covered us in a storm of flying sand. We stopped at a steep angle with Mann cursing and rubbing his sore head. Even through the brown swirling dust I could see what had made Percy swerve. There, not fifty yards away, was another Landrover — empty and abandoned. Even before the sand settled, Mann was out of the car and following the still visible tracks that the others had left. Red Bancroft had abandoned her shoes, and a man — Professor Bekuv — had stumbled and fallen leaving a long scar in the smooth sand.

We followed the tracks for fifty yards or so, and then they were replaced by wide shallow troughs, ridged with an even pattern of lines. Mann was the first to recognize the strange spoor. 'A dune buggy!' He hurried forward until he found a place where the softly inflated tyres had ballooned on the ridge of the next dune. 'No doubt about it — a dune buggy.' The curious little cars that Californians used for cavorting on beaches were the only vehicles that could outrun a Landrover in country like this.

'A dune buggy?' said Percy.

'Lightweight open vehicle,' I said. 'Moulded body, four wheels, specially made soft tyres with a very wide tread and a canvas top to shield you from the sun… roll-bar for protection, can be used to mount a heavy machine- gun…'

'What are you talking…' said Mann and then he raised his eyes to the ridge of the next dune, and he saw them too.

There were three men in the dune buggy. I studied them carefully for signs of their origin or allegiance. They had the very dark skin of the sort you see in the far south. Protecting their heads from the high sun they wore the howli, and their robes were ragged and dirty but had once been the boubou style of Mauritania far to the west. Their faces were impassive, but the man in the rear seat gave an imperious wave of the A.K.M.S. machine-pistol he was holding. Obedient to it we scrambled up the burning-hot sand.

They were patrolling, and, after walking another half hour, we caught sight of where they'd come from. It was bleached almost to the colour of the pale sand that surrounded it, a great fortress complete with crenellated walls and watch-towers. Ever since the Romans, armies had built such fortified encampments to dominate the caravan trails, wells and desert tracks. The French had built more, and used the Foreign Legion to man them. But there was no flag flying from the mast of this fort, only a tangle of shortwave aerials; dishes, rods, spirals, arrays, loops and frames, more antennae than I'd ever seen before in one place.

At first sight I had not realized the size of the fortress, but nearly an hour later, when we had still not reached its massive doors, I could see that its ramparts were as high as a six-storey building. Finally we reached it, and the Arabs herded us through the main entrance.

There were two sets of doors, and looking up I saw daylight through the sort of openings from which boiling oil was poured on to besieging knights. The second set of doors opened on to a courtyard. Parked there were more dune buggies and beyond them a helicopter. It looked like the little Kamov two-seater gun-ship that had chased Bekuv down the road on the day he defected, and shot up the car with the Arab boy in it. Now its blades had been removed, and a couple of mechanics were tinkering with the rotor linkage. But most of the courtyard was occupied by two huge radio telescopes, the dishes about sixty feet across. Bekuv was there, parading round the equipment and touching the controls and the wiring and the bowl-edge with the sort of tactile awe that most men reserve for very old cars or very new mistresses.

'Jesus Christ!' said Mann softly as he saw the radio telescopes and realized what they'd been used for. He called to Bekuv, 'Hey there, Professor. Are you all right?'

Bekuv looked at us for a long time before replying. Then he said, 'Come here.' It was a command. We shuffled over to him.

'Why didn't you tell us?' said Mann. 'Why didn't you say you'd set up this tracking station to milk the communications satellites. Was it your idea?'

Mann was unable to keep the admiration out of his voice, and Bekuv smiled in appreciation. He handed Mann a water flask that was hanging on the back of his seat. Mann drank some and passed it to Dempsey and then on to me. The water was warm and heavily chlorinated, but it was a welcome relief after our long walk through the sand.

Bekuv watched Mann all the time, studying his badly bruised face and the plaster — dirtied now — that could be seen under the brim of his hat. Bekuv's eyes were wide and glaring, or perhaps I was just being wise after the event. 'I thought you were dead,' he told Mann. 'I thought they shot you at the airport.'

'Yes, I'm sorry about that,' said Mann. He sat down on a broken packing-case and closed his eyes. The hike through the soft sand had exhausted him.

Bekuv said, 'I was right not to trust you. My wife guessed that there was no chair at New York University… she guessed that you were telling me all lies…'

'… and she arranged with Moscow that you could come back here,' said Mann. 'Yeah, yeah, yeah, we know all that. But why did you want to come back here?'

'She said I was to dismantle the apparatus and shred all my records,' said Bekuv.

'But you're not going to do that, are you?' I said.

'No,' said Bekuv. 'I'm going to continue my work. Last night I got signals from Tau Ceti.'

'Well, that's wonderful,' I said, feigning enthusiasm.

'Who's Tau Ceti?' said Mann.

'It's a star,' I told him. 'Professor Bekuv picked up signals from it last year.'

'Is that right?' said Mann.

'So you read those books I loaned you,' Bekuv said.

'And your lectures and the notes,' I said. 'I read everything.'

Bekuv waved a hand in the air and gabbled some fast Arabic. I couldn't follow it except to guess that he was telling the guards to take Mann and Percy Dempsey away somewhere. Bekuv took my arm and led me to the main building of the fortress. The walls were a yard thick and might have been here for centuries.

'How old is this place?' I asked, more in order to keep him affable than because I wanted to know. He reached into his pocket and brought out a handful of stone arrowheads of the sort that the nomad children sell in the southern villages.

'Roman,' he said. 'There must have been some sort of fort here ever since. We have water, you see. The siting leaves a lot to be desired but we have the only water for a hundred miles.' He pushed open the huge, iron- studded door. Inside, the fort was dark and even more bizarre. Shafts of hard Saharan sunlight stood like buttresses against the gaps in the shuttered windows. There was a huge staircase dappled with light that came from the broken parts of the roof, sixty feet above our heads. But the room into which Bekuv went was equipped as a modern office: a sleek desk, three easy chairs, Lenin on the wall and enough books to require the small folding