To Chris Priest — counsellor and friend.

The drive to Chivenor had been long and tiring. As it had progressed the pain in Hasson’s back had grown worse, and with the pain had come a steady deterioration of his mood. At first there had been stray misgivings, hints of sadness which anybody might have felt on passing through a series of towns and villages where all commerce and community life seemed to have been vanquished by the chill grey rains of Match. By the time they had reached the north Devon coast, however, Hasson felt more than normally dejected, and later when the car surmounted a rise giving its three occupants a glimpse of the Taw estuary — he realized he was terrified of the journey that lay ahead.

How can this be? he thought, unable to reconcile his feelings with those he would have experienced six weeks earlier in similar circumstances. I’m being given a free trip to Canada, three months” leave on full pay, all the time I need to rest and recuperate

“I always think there’s something right about the principle of the flying boat,” said Colebrook, the police surgeon, who was sitting in the rear seat with Hasson. “The whole idea of flying over the sea in ships, having four-fifths of the globe for a landing place

It all seems natural, if you know what I mean — technology and nature going hand-in-hand.”

Hasson nodded. “I see what you’re getting at.”

“Just look at those things.” A gesture of Colebrook’s plump, strong hand took in the slate-blue strip of water and the apparently haphazard scattering of flying boats. “Silver birds, as our Polynesian cousins might say. Do you know why they aren’t painted?”

Hasson shook his head, trying to take an interest in the surgeon’s conversation. “Can’t think.”

The load factor. Economics. The weight of the paint would be equal to the weight of an extra passenger.”

“Is that right?” Hasson smiled, hopelessly, and saw the boyish enthusiasm fade from Colebrook’s face to be replaced by a look of professional concern. He cursed himself for not having made a greater effort to cover up.

“Problems, Rob?” Colebrook turned bodily to get a better look at his patient, pulling his suit into silky diagonal folds across his stomach. “How do you feel?” “A bit tired that’s all. A few aches and pains. I’ll hang together.”

“I’m not asking about that side of it. Have you taken any Serenix today?”

“Well …” Hasson abandoned the attempt to lie. “I don’t like taking pills.”

“What’s that got to do with anything,” Colebrook said impatiently. “I don’t like brushing my teeth, but if I stop the result will be a lot of pain and a mouth full of delph — so I brush my teeth.”

“It’s hardly the same thing,” Hasson protested.

“it’s exactly the same thing, man. Your nervous system is bound to give you hell for a month or two, maybe longer, but the fact that a thing is natural doesn’t mean you have to put up with it. There aren’t any medals for this Rob — no Misery Cross or Depression Diploma…”

Hasson raised a finger. “That’s good, doc. I like that.”

“Swallow a couple of those caps, Rob. Don’t be a fool.” Colebrook, who had too much medical experience to allow himself to be upset by a wayward patient, leaned forward and tapped Air Police Captain Nun on his shoulder, his expansive mood returning. Why don’t we all go to Canada, Wilbur? We could all do with a break.”

Nun had been at the wheel most of the way from Coventry and was showing signs of strain. “Some of us can’t be spared,” he said, refusing to be captivated by pleasantries. “Anyway, it’s too early in the year for me. I’d rather wait till the Iceland-Greenland corridor is cleared.”

“That could take months.”

“I know, but some of us can’t be spared.” Nunn transferred the weight of his forearms on to the steering wheel, managing to convey his disinclination to talk. The sky ahead had cleared to an antiseptic pale blue, but the ground was still wet, and the car’s wheels made swishing sounds on the tarmac curves as it descended towards the airfield and flying boat terminal at Chivenor. Nunn continued to drive fast, with broody concentration, as the view of the estuary was lost behind a row of dripping evergreens.

Hasson, slouched uncomfortably in the rear seat, stared at the 8 back of his chief’s neck and wished there had been no reference to the clearing of the flight corridors. His plane was due to take off in little more than an hour and the last thing he wanted was to think about the possibility of it smashing into any human bodies which might be drifting through the low cloud and fog that often obscured the Atlantic air lines.

Nobody in the west had any clear idea of what was going on in the vast tracts of land spanning the eastern hemisphere from the Zemlayas to Siberia, but each winter a sparse, slow blizzard of frozen bodies — kept aloft by their CG harnesses — came swirling down over the pole, endangering air cargo traffic between Britain and North America.

The general belief was that they were Asian peasants, ignorant of the dangers of boosting to even a modest altitude in a continental winter, or victims of sudden weather changes who had been claimed by frostbite without realising what was happening to them. A hysterical faction, small but vociferous, claimed they were political expendables deliberately cast loose on the geostrophic winds to hinder, even marginally, the flow of western commerce. Hasson had always regarded the latter idea as being unworthy of his consideration, and the fact that it had entered his mind now was yet another pointer to his state of health. He slid his hand into his coat pocket and gripped the container of Serenix capsules, reassuring himself they were available.

In a few minutes the car had reached the airfield and was skirting its perimeter on the way to the flying boat docks. The tall silvery fins of the boats could be seen here and there above the complex of quayside sheds and portable offices. A number of men, their clothing marked with dayglo panels, were flying between the quay and the boats anchored further out in the estuary, registering on the edge of Hasson’s vision as a constant agitation of colourful specks.

Nunn brought the car to a halt in a parking bay which was outside the mesh fence of the departure area. As Hasson’s department head, he had been burdened with most of the behind-the scenes work associated with smuggling Hasson out of the country and finding a place where he could live in safe obscurity for three months. No formal machinery existed for hiding and protecting key witnesses whose lives could be under threat, and 9 Captain Nunn had been put to considerable trouble to find a suitable host for Hasson in another country. In the end he had come to an arrangement with a Canadian police officer who had been on an exchange visit to the Coventry force some years earlier. Nun was a man who hated anything to upset his administrative routine and now he was anxious to get Hasson off his hands.

“We won’t go in with you, Rob,” he said, switching off the engine. “The Less we’re seen together the better. No point in taking any chances.”

“Chances!” Hasson snorted to show his disapproval of what he thought of as a charade. “What chances? Sullivan is a mobster, but he’s also a business man and he knows he’ll be finished if he starts killing cops.”

Nun drummed with his fingers on the serrated rim of the steering wheel. “We’re not cops Rob — we’re air cops. And people kill us all the time. How many of your original squad are still alive?”

“Not many.” Hasson turned his head away to hide an unexpected, unmanning quiver of his lower lip.

“I’m sorry — I shouldn’t have said that.” Nunn sounded irritated rather than apologetic.