It was fear that, eight years after the war, still reduced him to the swearing and mechanically filthy reactions and utterances of the common soldiery. He looked about him, distracting himself from his terror by examining the other lunatics queuing up to experience three hours of danger and discomfort.

Rich, expensively dressed and unrestrainedly loud, they smiled when they showed their passports and plane tickets, keen to be off. They waved goodbye to their Vuitton luggage, their hat boxes, golf clubs and tennis racquets, as a uniformed employee of Imperial Airways wheeled it all away on a trolley to be stowed in the hold. Joe clutched his Gladstone bag and briefcase firmly when his turn came to face the booking clerk, his steely expression discouraging any attempt to wrest them from him.

‘My luggage has gone ahead. I’ll be keeping these with me,’ he said firmly, flashing his warrant card. ‘Work to do during the flight, you understand.’

‘As long as the light lasts, sir,’ the clerk agreed reluctantly. ‘Will you be requiring supper during the flight, may I ask? I believe we have Whitstable oysters and breast of duck on the menu this evening, sir.’

Joe tried to disguise an automatic shudder. ‘Thank you but I shall have to decline.’ He smiled. ‘Late dinner plans in Paris.’ The reciprocal smile showed complete understanding.

‘Full complement of passengers tonight?’ Joe enquired politely as his tickets were checked and chalk scrawls made on his bags by a second employee.

‘No, sir. By no means. Thirteen passengers. You’re the thirteenth. We can take twenty at a push but the season isn’t in full swing yet. You’ll find it pleasantly uncrowded. Fine clear skies reported over the Channel,’ he concluded encouragingly.

‘This lot must be first-time flyers,’ Joe decided as he shuffled along in file with the chattering group ahead of him to take a temporary seat in a room equipped as a lounge. ‘They won’t be grinning and giggling for much longer.’ One of his friends, like-minded, had summed up the short flight: ‘They put you in a tin coffin and shut the lid. You’re sprayed with oil and stunned with noise. You’re sick into a bag . . . twice . . . and then you land in Paris.’

The passengers, who all seemed to know each other, swirled around the quiet, dark man absorbed by his documents, offering no pleasantries, attempting no contact. Something about the stern face, handsome if you were sitting to the east of him, rather a disaster if you found yourself to the west . . . war wound, obviously . . . kept them at arm’s length. The men sensed an implacable authority, the women glanced repeatedly, sensing a romantic challenge. Everything about him, from the set of his shoulders to the shine on his shoes, suggested a military background though the absence of uniform, medals, regimental tie or any other identifying signs made this uncertain. His dark tweed suit was of fashionably rugged cut and would not have looked out of place on the grouse moor or strolling round the British Museum. The leather briefcase at his feet was a good one though well-worn, and spoke of the businessman hurrying to Paris. But there were disconcerting contradictions about the man. The black felt fedora whose wide brim he’d pulled low over his eyes gave him a bohemian air and the gaily coloured silk Charvet scarf knotted casually about his neck was an odd note and, frankly . . . well . . . a little outré. An artist perhaps? No – too well dressed. Architect? One of those art deco chappies? Bound no doubt for the exhibitions that came and went along the Seine.

Apretty redhead wearing a sporty-looking woollen two-piece and a green cloche hat changed places with one of her friends to sit beside the stranger. She leaned slightly to catch a glimpse of the papers which were so absorbing him. Joe wondered what on earth she would make of the learned treatise he was scanning: Identification of Corpses by G. A. Fanshawe, D.Sc. (Oxon) with its subheadings of Charred Bodies, Drowned Bodies, Battered Bodies . . .

Aware of her sustained curiosity, Joe mischievously shuffled to the top a printed sheet of writing paper. Under the bold insignia of Interpol, and laid out in letters so large she would have no difficulty in reading them, was an invitation to The Commissioner of the Metropolitan Police, Scotland Yard, London, to attend the second conference of Heads of Interpol in Paris. A detailed programme of lectures and events followed. Joe took out a pencil and began to make notes in the margin.

She addressed him with the open confidence of a fellow passenger aboard a boat, all companions for the duration of the voyage. ‘I see you’re not on pleasure bent in the capital of frivolity? Er . . . Commissioner? Should I address you as Commissioner? Is that who you are?’

He grinned and passed her a card. ‘Not Commissioner, I’m sorry to say. He’s the villain who’s deputized me to come along in his stead. This is me. I’m Joseph Sandilands. How do you do, Miss . . .?’

‘Watkins. Heather Watkins.’ And she read: ‘Commander Sandilands. DSO. Légion d’honneur. Ah, I was right! I took you for a military or naval man of some sort. But Commander sounds very impressive!’ And she added in a tone playfully inquisitive: ‘May we look to see “Commissioner” on your card one day?’

‘I do hope not! Annoying my boss is one of my chief recreations. I should hate to find myself at the top of the pyramid keeping order. Who would there be to keep me in order? I should have to do it myself!’ Good Lord! That was the first time he’d given words to any such feeling. And he’d expressed it in unbelievably artless words to a complete stranger. It must be the fear of the next few hours that was sweeping away his defences, making him reckless.

The arrival of a steward in Imperial Airways livery made unnecessary any further revelations and they were called for boarding. The group, jostling and joking with each other, surged forward. But, at the point of putting her foot on the ramp, the lively and confident Miss Watkins, who had trailed behind finishing a conversation with Joe, balked. She shook her head like a horse refusing a fence, turned pale and began to breathe raggedly. Joe, close behind, recognized the symptoms and put a comforting arm under hers. ‘Don’t worry,’ he said. ‘And, above all, don’t be concerned if the wings appear to wobble alarmingly. They’re supposed to do that. Watch them carefully and, should they stop wobbling, then you may start to worry. These big planes are perfectly safe, you know, and the company has an unblemished record. Look – do you see – it’s an Argosy. That means it’s got four wings, three engines and two pilots. That should be enough to get us through.’ He wished he could believe all this rot himself. ‘And, look, Miss Watkins . . . Heather . . . take this. I find it really helps.’ He passed her a lump of barley sugar.

A second steward in spanking white mess jacket and white peaked cap welcomed them aboard what he proudly called ‘the Silver Wing service’ and, taking them for a couple, ushered them towards a pair of seats alongside at the rear of the plane.

‘Every passenger has a window seat, you see,’ said Joe, helping her to settle. ‘Though you can always draw the curtain across, should you have vertigo.’

They braced themselves for take-off. It came with the usual terrifying snarls of the engine and bumps along the runway and then there was the stomach-clenching moment of realization that the machine had torn itself free of the earth and was soaring at an impossible angle upwards. A glance through the oil-spattered glass showed the grey blur of London disappearing below them. Higher up, the sunlight brightened and they caught the full glow of the westering sun gilding the meadows and woods of southern England.

‘It will be dark before we arrive, won’t it?’ Heather Watkins asked, suffering a further pang of apprehension.