'Take a good look at the old boy,' he whispered. 'That's the fellow we're after; Lord Gavin Fortescue's his name. Looks like an archbishop, doesn't he, but he probably deserves to die kicking at the end of a rope more than any man in Europe. Think you'd know him again?'
'Sure thing, sir,' Rudd whispered back. 'Looks like a monkey on a stick ter me, but 'e's got a distinguished sort of dial I will say. And ain't his girl friend a bit of orlright.'
Lord Gavin was talking in a quick low voice to 'Corot'. The watchers could not catch his words but they saw him pass over a sheaf of papers.
The handsome knife thrower touched his checked cap; then closed the car door and it was driven away at a high speed towards Boulogne.
For a second Gregory considered attacking the thug for the purpose of seizing the papers he had just received from Lord Gavin, but the chances were that, if they set on him, his shouts would bring his four friends tumbling out of the cafe before they could master him and get away. In any case, Gregory decided, more valuable information would probably be obtained by remaining under cover for the time being and following the man to see where he went.
'Corot' only waited long enough for the dust, thrown up by the car, to disperse, then he returned to the estaminet; but only to poke his head inside the door.
A moment later, the four others joined him outside and, as the whole party set off together up the road, Gregory saw that all five of them were now carrying things that looked like fat cylinders or oil drums, slung across their backs.
He gave them a few minutes' start; then followed. It was easy to keep the group in view as the road switched backed towards the rising ground and on each low crest they stood out plainly silhouetted against the starlit sky. After a mile they left the main road and took a track leading in the direction of the coast. Along this Gregory and Rudd had more difficulty in keeping sight of them as it wound in and out among the dips and hillocks of the deserted down land.
No lights were to be seen in any direction and Gregory knew that they were now well inside that desolate windswept triangle, entirely lacking in roads and villages, which lies between the three points; Boulogne, Calais and Cape Gris Nez.
A good two miles were covered, then the Frenchmen turned in the direction of Boulogne again, leaving the track to trudge over the short coarse grass. There was little cover in this open country which made the shadowing of them more difficult. Gregory had to drop much further behind, allowing them time to mount each gentle slope and disappear into the next shallow valley before he and Rudd dared to move on again, in case one of them should turn suddenly and realise that they were being followed.
Twice Gregory lost his quarry for a moment "but on each occasion he managed to pick them up again because, all unsuspicious, they were laughing and talking as they walked, and their voices carried clearly on the light airs of the still warm night.
They had long since left behind the last twinkling lights of Calais Town. It was over an hour since they had left the inn and in all that time they had not passed a single farmstead or seen a human being. As the slopes began to rise more steeply Gregory realised that they were moving towards the high ground which dominates that uninhabited area and is known as Mont Couple.
The group in front suddenly fell silent and must have turned off in a new direction for Gregory lost the shadowy blur of their moving figures in the semidarkness for the third time, and now, although he chanced discovery by trotting forward a hundred yards he failed to regain touch with them.
Cursing his ill luck he stumbled up a low mound and, pulling his night glasses from his raincoat pocket, began to scan the surrounding country. For ten minutes or more, with Rudd beside him, he swept the darkened down lands, first in one direction then in another, without success, until he suddenly caught sight of a faint glow which had just appeared a quarter of a mile away, throwing the line of the next ridge up into sharp relief.
For a moment he thought it might be caused by the lighthouse at Boulogne, but that had a sweeping beam, whereas this remained steady. With a word to Rudd he thrust his night glasses back in his pocket and they set off towards it.
As they advanced the silvery glow grew perceptibly brighter, throwing all the surrounding country into a heavier darkness. Halfway up the ridge Gregory suddenly slipped to his knees pulling Rudd down beside him. From that point they wriggled up the last hundred yards on their stomachs. At the crest Gregory caught Rudd's arm to stop him proceeding further and gave a low chuckle.
Below them stretched a broad shallow dip in the very centre of the high ground they had been traversing. The men they had followed had already set up two of their cylinders, from which there now hissed bright acetylene burners, and were busy with a third at the far end of the valley bottom. Soon they had completed their work and had all five flares going, spaced at irregular intervals, but marking out a fiery T at one end of a fine stretch of level grassy land hidden from any casual observer beyond its ring of encircling hills.
Suddenly Gregory pricked up his ears. He had caught the hum of an aeroplane. A moment later the noise ceased and a big bomber passed low overhead outlined in black silhouette against the starry sky then, sinking rapidly, came to land over the flares, taking its wind direction from their formation.
Its pilot taxied it towards the further slope and there the five men met it; but Gregory's attention was taken from it momentarily by the sound of another plane coming up from a different quarter which circled slowly overhead, came down into the wind, and taxied up alongside the first arrival.
For the next quarter of an hour plane after plane arrived at little more than minute intervals; but Gregory's eyes were now riveted upon the activities of the men on the ground. Their number had increased to half a hundred and these had not landed from any of the planes. They were emerging from a shadowy patch at the far side of the valley and all carried cases or bales upon their shoulders which they were busily loading into the first few aeroplanes to arrive at this secret depot.
At first Gregory was puzzled as to where the men with supplies were coming from. There were no roads or tracks within a couple of miles of this lonely spot so they could not have been brought by motor or lorry and no dumps were to be seen; although the men kept disappearing into the shadows in an irregular chain to return each time carrying a fresh load of cargo for the waiting fleet.
Touching Rudd on the arm he began to crawl stealthily along the crest of the ridge, keeping just within the belt of shadow, until he could get a better view of the place from which this chain of supplies continued to make its mysterious appearance.
After covering two hundred yards he was able to view the proceedings from a fresh angle and noticed what looked like a black slit in the seaward slope of the natural basin below them. It must be, he guessed, the entrance to an underground passage leading down through the old chalk caves to one of the little fishing villages, Sandgatt or Wissant, on the coast a mile or so away.
Rudd had been drilled to silence in the old days when, as Gregory's batman, they had gone out together time and again into 'no man’s land' on the western front; but now he could restrain his curiosity no longer.
'What's the game, sir?' he asked in a hoarse whisper.