"Sarge? Radio." It was the R/T operator.

Parkin walked back and took the handset from him. "Sergeant Parkin."

"Major Roberts. You're discharged from active duty as of now, Sergeant."

"Why?" Parkin's first thought was that they had discovered his true age.

"The brass want you in London. Don't ask me why because I don't know. Leave your corporal in charge, and make your way back to base. A car will meet you on the road."

"Yes, sir."

"The orders also say that on no account are you to risk your life. Got that?"

Parkin grinned, thinking of the clock tower and the dynamite. "Got it."

"All right. On your way. You lucky sod."

Everyone had called him a boy, but they had known him before he joined the Army, Bloggs thought. There was no doubt he was a man now. He walked with confidence and grace, looked about him sharply, and was respectful without being ill at ease in the company of superior officers. Bloggs knew that he was lying about his age, not because of his looks or manner, but because of the small signs that appeared whenever age was mentioned-signs that Bloggs, an experienced interrogator, picked up out of habit.

He had been amused when they told him they wanted him to look at pictures. Now, on his third day in Mr Middleton's dusty Kensington vault, the amusement had gone and tedium had set in. What irritated him most was the no-smoking rule.

It was even more boring for Bloggs, who had to sit and watch him.

At one point Parkin said, "You wouldn't call me back from Italy to help in a four-year-old murder case that could wait until after the war. Also, these pictures are mostly of German officers. If this case is something I should keep quiet about, you'd better tell me."

"It's something you should keep quiet about," said Bloggs.

Parkin went back to his pictures.

They were all old, mostly browned and fading. Many were out of books, magazines, and newspapers. Sometimes Parkin picked up a magnifying glass Mr Middleton had thoughtfully provided, to peer more closely at a tiny face in a group: and each time this happened Bloggs' heart raced, only to slow down when Parkin put the glass to one side and picked up the next photograph. They went to a nearby pub for lunch. The ale was weak, like most wartime beer, but Bloggs still thought it wise to restrict young Parkin to two pints. On his own he would have sunk a gallon.

"Mr Faber was the quiet sort," Parkin said. "You wouldn't think he had it in him. Mind you, the landlady wasn't bad looking. And she wanted it. Looking back, I think I could have had her myself if I'd known how to go about it. There, I was only eighteen."

They ate bread and cheese, and Parkin swallowed a dozen pickled onions. When they went back they stopped outside the house while Parkin smoked another cigarette.

"Mind you," he said, "he was a biggish chap, good-looking, well-spoken. We all thought he was nothing much because his clothes were poor and he rode a bike and he'd no money. I suppose it could have been a subtle kind of disguise." His eyebrows were raised in a question.

"It could have been," Bloggs said.

That afternoon Parkin found not one but three pictures of Faber. One of them was only nine years old. And Mr Middleton had the negative.

Heinrich Rudolph Hans von Muller-Guder (also known as Faber) was born on May 26, 1900, at a village called Oln in West Prussia. His father's family had been substantial landowners in the area for generations. His father was the second son; so was Heinrich. All the second sons were Army officers. His mother, the daughter of a senior official of the Second Reich, was born and raised to be an aristocrat's wife, and that was what she was.

At the age of thirteen Heinrich went to the Karlsruhe cadet school in Baden; two years later he was transferred to the more prestigious Gross-Lichterfelde, near Berlin. Both places were hard disciplinarian institutions where the minds of the pupils were improved with canes and cold baths and bad food. However, Heinrich learned to speak English and French and studied history, and passed the final examinations with the highest mark recorded since the turn of the century. There were only three other points of note in his school career: one bitter winter he rebelled against authority to the extent of sneaking out of the school at night and walking 150 miles to his aunt's house; he broke the arm of his wrestling instructor during a practice bout; and he was flogged for insubordination.

He served briefly as an ensign-cadet in the neutral zone of Friedrichsfeld, near Wesel, in 1920: did token officer training at the War School at Metz in 1921, and was commissioned Second Lieutenant in 1922.

("What was the phrase you used?" Godliman asked Bloggs, "German equivalent of Eton and Sandhurst?")

Over the next few years he did short tours of duty in half a dozen places, in the manner of one who is being groomed for the general staff. He continued to distinguish himself as an athlete, specialising in long-distance running. He made no close friendships, never married, and refused to join the National Socialist party. His promotion to lieutenant was somewhat delayed by a vague incident involving the pregnancy of the daughter of a lieutenant colonel in the Defence Ministry, but eventually came about in 1928. His habit of talking to superior officers as if they were equals came to be accepted as pardonable in one who was both a rising young officer and a Prussian aristocrat.

In the late '20s Admiral Wilhelm Canaris became friendly with Heinrich's Uncle Otto, his father's elder brother, and spent several holidays at the family estate at Oln. In 1931 Adolf Hitler, not yet Chancellor of Germany, was a guest there.

In 1933 Heinrich was promoted to captain, and went to Berlin for unspecified duties. This is the date of the last photograph.

About then, according to published information, he seems to have ceased to exist...

"We can conjecture the rest," said Percival Godliman. "The Abwehr trains him in wireless transmission, codes, map-making, burglary, blackmail, sabotage, and silent killing. He comes to London in about 1937 with plenty of time to set himself up with a solid cover, perhaps two. His loner instincts are honed sharp by the spying game. When war breaks out, he considers himself licenced to kill." He looked at the photograph on his desk. "He's a handsome fellow."

It was a picture of the 5,000 metres running team of the 10th Hanoverian Jaeger Battalion. Faber was in the middle, holding a cup. He had a high forehead, with cropped hair, a long chin, and a small mouth decorated with a narrow moustache.

Godliman passed the picture to Billy Parkin. "Has he changed much?"

"He looked a lot older, but that might have been his... bearing." He studied the photograph thoughtfully "His hair was longer, and the moustache was gone." He passed dhe picture back across the desk. "But it's him all right."

"There are two more items in the file, both of them conjectural," Godliman said. "First, they say he may have gone into Intelligence in 1933-that's the routine assumption when an officer's record just stops for no apparent reason. The second item is a rumour, unconfirmed by any reliable source, that he spent some years as a confidential advisor to Stalin, using the name Vasily Zankov."

"That's incredible," Bloggs said. "I don't believe that."

Godliman shrugged. "Somebody persuaded Stalin to execute the cream of his officer corps during the years Hitler rose to power."

Bloggs shook his head, and changed the subject. "Where do we go from here?"

Godliman considered. "Let's have Sergeant Parkin transferred to us. He's the only man we know who has actually seen Die Nadel. Besides, he knows too much for us to risk him in the front line; he could get captured and interrogated. Next, make a first-class print of this photo, and have the hair thickened and the moustache obliterated by a retouch artist. Then we can distribute copies."

"Do we want to start a hue and cry?" Bloggs said doubtfully.

"No. For now, let's tread softly. If we put the thing in the newspapers he'll get to hear of it and vanish. Just send the photo to police forces for the time being."

"Is that all?"

"I think so. Unless you've got other ideas."

Parkin cleared his throat. "Sir?"

"Yes."

"I really would prefer to go back to my unit. I'm not really the administrative type, if you see what I mean."

"You're not being offered a choice, Sergeant. At this stage, one Italian village more or less makes relatively little difference but this man Faber could lose us the war. Truly."

Faber had gone fishing.

He was stretched out on the deck of a thirty-foot boat, enjoying the spring sunshine, moving along the canal at about three knots. One lazy hand held the tiller, the other rested on a rod that trailed its line in the water behind the boat. He hadn't caught a thing all day.

As well as fishing, he was bird-watching, both out of interest (he was actually getting to know quite a lot about the damn birds) and as an excuse for carrying binoculars. Earlier today he had seen a kingfisher's nest.

The people at the boatyard in Norwich had been delighted to rent him the vessel for a fortnight. Business was bad they had only two boats nowadays, and one of them had not been used since Dunkirk. Faber had haggled over the price, just for the sake of form. In the end they had thrown in a locker full of tinned food.

He had bought bait in a shop nearby; the fishing tackle he had brought from London. They had observed that he had nice weather for it, and wished him good fishing. Nobody asked to see his identity card. So far, so good.

The difficult bit was to come. For assessing the strength of an army was difficult. First, for example, you had to find it.

In peacetime the Army would put up its own road signs to help you. Now they had been taken down, not only the Army's but everyone else's road signs.

The simple solution would be to get in a car and follow the first military vehicle you saw until it stopped. However, Faber had no car; it was close to impossible for a civilian to hire one, and even if you got one you couldn't get petrol for it. Besides, a civilian driving around the countryside following Army vehicles and looking at Army camps was likely to be arrested.

Hence the boat.

Some years ago, before it had become illegal to sell maps, Faber had discovered that Britain had thousands of miles of inland waterways. The original network of rivers had been augmented during the nineteenth century by a spider web of canals. In some areas there was almost as much waterway as there was road. Norfolk was one of these areas.

The boat had many advantages. On a road, a man was going somewhere; on a river he was just sailing. Sleeping in a parked car was conspicuous; sleeping in a moored boat was natural. The waterway was lonely. And who ever heard of a canal-block?

There were disadvantages. Airfields and barracks had to be near roads, but they were located without reference to access by water. Faber had to explore the countryside at night, leaving his moored boat and tramping the hillsides by moonlight, exhausting forty-mile round trips during which he could easily miss what he was looking for because of the darkness or because he simply did not have enough time to check every square mile of land.

When he returned, a couple of hours after dawn, he would sleep until midday, then move on, stopping occasionally to climb a nearby hill and check the outlook. At locks, isolated farmhouses, and riverside pubs he would talk to people, hoping for hints of a military presence. So far there had been none.

He was beginning to wonder whether he was in the right area. He had tried to put himself in General Patton's place, thinking: If I were planning to invade France east of the Seine from a base in eastern England, where would I locate that base?

Norfolk was obvious: a vast expanse of lonely countryside, plenty of flat ground for aircraft, close to the sea for rapid departure. And the Wash was a natural place to gather a fleet of ships. However, his guesswork might be wrong for reasons unknown to him. Soon he would have to consider a rapid move across country to a new area-perhaps the Fens.

A lock appeared ahead of him, and he trimmed his sails to slow his pace. He glided gently into the lock and bumped softly against the gates. The lock-keeper's house was on the bank. Faber cupped hands around his mouth and helloed. Then he settled down to wait. He had learned that lock-keepers were a breed that could not be hurried. Moreover, it was tea time, and at tea time they could hardly be moved at all.

A woman came to the door of the house and beckoned. Faber waved back, then jumped onto the bank, tied up the boat and went into the house. The lock-keeper was in his shirtsleeves at the kitchen table. He said, "Not in a hurry, are you?"

Faber smiled. "Not at all."

"Pour him a cup of tea, Mavis."

"No, really," Faber said politely.

"It's all right, we've just made a pot."

"Thank you." Faber sat down. The little kitchen was airy and clean, and his tea came in a pretty china cup. "Fishing holiday?" the lock-keeper asked.

"Fishing and bird-watching." Faber answered. "I'm thinking of tying up quite soon and spending a couple of days on land."

"Oh, aye. Well, best keep to the far side of the canal, then. Restricted area this side."

"Really? I didn't know there was Army land hereabouts."

"Aye, it starts about half a mile from here. As to whether it's Army, I wouldn't know. They don't tell me."

"Well, I suppose we don't need to know," Faber said.

"Aye. Drink up, then, and I'll see you through the lock. Thanks for letting me finish my tea."

They left the house, and Faber got into the boat and untied it. The gates behind him closed slowly, and then the keeper opened the sluices. The boat gradually sank with the level of the water in the lock, then the keeper opened the front gates.

Faber made sail and moved out. The lock-keeper waved.

He stopped again about four miles away and moored the boat to a stout tree on the bank. While he waited for night to fall he made a meal of tinned sausage meat, dry biscuits, and bottled water. He dressed in his black clothes, put into a shoulder bag his binoculars, camera, and copy of Rare Birds of East Anglia, pocketed his compass, and picked up his flashlight. He was ready.

He doused the hurricane lamp, locked the cabin door and jumped onto the bank. Consulting his compass by flashlight, he entered the belt of woodland along the canal.

He walked due south from his boat for about half a mile until he came to the fence. It was six feet high, chicken wire, with coiled barbed wire on top. He backtracked into the wood and climbed a tall tree.

There was scattered cloud above. The moon showed through fitfully. Beyond the fence was open land, a gentle rise. Faber had done this sort of thing before, at Biggin Hill, Aldershot, and a host of military areas all over southern England. There were two levels of security: a mobile patrol around the perimeter fence, and stationary sentries at the installations. Both, he felt, could be evaded by patience and caution.

Faber came down the tree and returned to the fence. He concealed himself behind a bush and settled down to wait.

He had to know when the mobile patrol passed this point. If they did not come until dawn he would simply return the following night. If he was lucky they would pass shortly. From the apparent size of the area under guard he guessed they would only make one complete tour of the fence each night.

He was lucky. Soon after ten o'clock he heard the tramp of feet, and three men marched by on the inside of the fence. Five minutes later Faber crossed the fence.

He walked due south; when all directions are equal, a straight line is best. He did not use his flashlight. He kept close to hedges and trees when he could, and avoided high ground where he might be silhouetted against a sudden flash of moonlight.

The sparse countryside was an abstract in black, grey, and silver. The ground underfoot was a little soggy, as if there might be marshes nearby. A fox ran across a field in front of him, as fast as a greyhound, as graceful as a cat.

It was 11:30 P.M. when he came across the first indications of military activity and very odd indications they were.

The moon came out and he saw, perhaps a quarter of a mile ahead, several rows of one-story buildings laid out with the unmistakable precision of an Army barracks. He dropped to the ground immediately, but he was already doubting the reality of what he apparently saw; for there were no lights and no noise.

He lay still for ten minutes, to give explanations a chance to emerge, but nothing happened except that a badger lumbered into view, saw him, and made off. Faber crawled forward.

As he got closer he realised that the barracks were not just unoccupied, but unfinished. Most of them were little more than a roof supported by cornerposts. Some had one wall.

A sudden sound stopped him: a man's laugh. He lay still and watched. A match flared briefly and died, leaving two glowing red spots in one of the unfinished huts. Guards.

Faber touched the stiletto in his sleeve, then began to crawl again, making for the side of the camp away from the sentries.

The half-built huts had no floors and no foundations. There were no construction vehicles around, no wheel-barrows, concrete mixers, shovels or piles of bricks. A mud track led away from the camp across the fields, but spring grass was growing in the ruts; it had not been used much lately.

It was as if someone had decided to billet 10,000 men here, then changed his mind a few weeks after building started.

Yet there was something about the place that did not quite fit that explanation.

Faber walked around softly, alert lest the sentries should take it into their heads to make a patrol. There was a group of military vehicles in the centre of the camp. They were old and rusting, and had been degutted: none had an engine or any interior components. But if one was going to cannibalise obsolete vehicles, why not take the shells for scrap? Those huts which did have a wall were on the outermost rows, and their walls faced out. It was like a film set, not a building site. Faber decided he had learned all he could from this place. He walked to the east edge of the camp, then dropped to his hands and knees and crawled away until he was out of sight behind a hedge. Half a mile further on, near the top of a rise, he looked back. Now it looked exactly like a barracks again.

The glimmer of an idea formed in his mind. He gave it time.

The land was still relatively flat, relieved only by gentle folds. There were patches of woodland and marshy scrub that Faber took advantage of. Once he had to detour around a lake, its surface a silver mirror under the moon. He heard the hoot of an owl, and looked in that direction to see a tumbledown barn in the distance. Five miles on he saw the airfield.

There were more planes here than he thought were possessed by the entire Royal Air Force. There were Pathfinders to drop flares, Lancasters and American B-17s for softening-up bombing, Hurricanes and Spitfires and Mosquitoes for reconnaissance and strafing; enough planes for an invasion.

Without exception their undercarriages had sunk into the soft earth and they were up to their bellies in mud. Once again there were no lights and no noise.

Faber followed the same procedure, crawling flat toward the planes until he located the guards. In the middle of the airfield was a small tent. The faint glow of a lamp shone through the canvas. Two men, perhaps three.

As Faber approached the planes they seemed to become flatter, as if they had all been squashed.

He reached the nearest and touched it in amazement. It was a piece of half-inch plywood, cut out in the outline of a Spitfire, painted with camouflage, and roped to the ground. Every other plane was the same. There were more than a thousand of them.

Faber got to his feet, watching the tent from the corner of his eye, ready to drop to the ground at the slightest sign of movement. He walked all around the phony airfield, looking at the phony fighters and bombers, connecting them with the movie-set barracks, reeling at the implications of what he had found.

He knew that if he continued to explore he would find more airfields like this, more half-built barracks. If he went to the Wash he would find a fleet of plywood destroyers and troop ships. It was a vast, meticulous, costly, outrageous trick.

Of course it could not possibly fool an onlooker for very long. But it was not designed to deceive observers on the ground. It was meant to be seen from the air.

Even a low-flying reconnaissance plane equipped with the latest cameras and fast film would come back with pictures that indisputably showed an enormous concentration of men and machines.

No wonder the general staff was anticipating an invasion east of the Seine.

There would be other elements to the deception, he guessed. The British would refer to FUSAG in signals, using codes they knew to be broken. There would be phony espionage reports channelled through the Spanish diplomatic bag to Hamburg. The possibilities were endless.

The British had had four years to arm themselves for this invasion. Most of the German army was fighting Russia. Once the Allies got a toehold on French soil they would be unstoppable. The Germans' only chance was to catch them on the beaches and annihilate them as they came off the troop ships.

If they were waiting in the wrong place, they would lose that one chance.

The whole strategy was immediately clear. It was simple, and it was devastating.

Faber had to tell Hamburg. He wondered whether they would believe him.

War strategy was rarely altered on the word of one man. His own standing was high, but was it that high?

That idiot Von Braun would never believe him. He'd hated Faber for years and would grab at the opportunity to discredit him. Canaris, Von Roenne... he had no faith in them.

And there was another thing: the radio. He didn't want to trust this to the radio... he'd had the feeling for weeks now that the radio code wasn't safe anymore. If the British found out that their secret was blown...

There was only one thing to do: he had to get proof, and he had to take it himself to Berlin. He needed photographs.

He would take photographs of this gigantic dummy army, then he would go to Scotland and meet the U-boat, and he would deliver the pictures personally to the Fuehrer. He could do no more. No less.

For photography he needed light. He would have to wait until dawn. There had been a ruined barn a little way back; he could spend the rest of the night there.

He checked his compass and set off. The barn was further than he thought, and the walk took him an hour. It was an old wooden building with holes in the roof. The rats had long ago deserted it for lack of food, but there were bats in the hayloft.

Faber lay down on some planks but he could not sleep. Not with the knowledge that he was now personally capable of altering the course of the war. Dawn was due at 05:21. At 04:20 Faber left the barn.

Although he had not slept, the two hours had rested his body and calmed his mind, and he was now in fine spirits. The cloud was clearing with a west wind, so although the moon had set there was starlight.

His timing was good. The sky was growing perceptibly brighter as he came in sight of the "airfield."

The sentries were still in their tent. With luck, they would be sleeping. Faber knew from his own experience of such duties that it was hardest to stay awake during the last few hours. But if they did come out, he would have to kill them.

He selected his position and loaded the Leica with a 36-frame roll of 35mm fast Agfa film. He hoped the film's light-sensitive chemicals had not spoiled; it had been stored in his suitcase since before the war, and you couldn't buy film in Britain nowadays. It should be all right; he had kept it in a lightproof bag away from any heat.

When the red rim of the sun edged over the horizon he began shooting. He took a series of shots from different vantage points and various distances, finishing with a close-up of one dummy plane; the pictures would show both the illusion and the reality.

As he took the last, he saw movement from the corner of his eye. He dropped flat and crawled under a plywood Mosquito. A soldier emerged from the tent, walked a few paces, and urinated on the ground. The man stretched and yawned, then lit a cigarette. He looked around the airfield, shivered, and returned to the tent. Faber got up and ran.

A quarter of a mile away he looked back. The airfield was out of sight. He headed west, toward the barracks.

This would be more than an ordinary espionage coup. Hitler had had a life of being the only one in step. The man who brought the proof that, yet again, the Fuehrer was right and all the experts were wrong, could look for more than a pat on the back. Faber knew that already Hitler rated him the Abwehr's best agent. This triumph might well get him Canaris' job. If he made it.

He increased his pace, jogging twenty yards, walking the next twenty, and jogging again, so that he reached the barracks by 06:30. It was bright daylight now, and he could not approach close because these sentries were not in a tent but in one of the wall-less huts with a clear view all around them. He lay down by the hedge and took his pictures from a distance. Ordinary prints would just show a barracks, but big enlargements ought to reveal the details of the deception.

When he headed back toward the boat he had exposed thirty frames. Again he hurried, because he was now terribly conspicuous, a black-clad man in the open fields of a restricted area. He reached the fence an hour later, having seen nothing but wild geese. As he climbed over the wire, he felt a great release of tension. Inside the fence the balance of suspicion had been against him; outside it was in his favour. He could revert to his bird-watching, fishing, sailing role. The period of greatest risk was over. He strolled through the belt of woodland, catching his breath and letting the strain of the night's work seep away.

He would sail a few miles on, he decided, before mooring again to catch a few hours' sleep.

He reached the canal. It was over. The boat looked pretty in the morning sunshine. As soon as he was under way he would make some tea.

A man in uniform stepped out of the cabin of the boat and said: "Well, well. And who might you be?"

Faber stood still, letting the icy calm and the old instincts come into play. The intruder wore the uniform of a captain in the Home Guard. He had some kind of handgun in a holster with a buttoned flap. He was tall and rangy, but he looked to be in his late fifties. White hair showed under his cap. He made no move to draw his gun. Faber took all this in as he said, "You are on my boat, so I think it is I who should ask who you are."

"Captain Stephen Langham, Home Guard."

"James Baker." Faber stayed on the bank. A captain did not patrol alone.

"And what are you doing?"

"I'm on holiday."

"Where have you been?"

"Bird-watching."

"Since before dawn? Cover him, Watson."

A youngish man in denim uniform appeared on Faber's left, carrying a shotgun. Faber looked around. There was another man to his right and a fourth behind him.

The captain called, "Which direction did he come from, corporal?"

The reply came from the top of an oak tree. "From the restricted area, sir."

Faber was calculating odds. Four to one until the corporal came down from the tree. They had only two guns: the shotgun and the captain's pistol. And they were basically amateurs. The boat would help too.

He said, "Restricted area? All I saw was a bit of fence. Look, do you mind pointing that blunderbuss away? It might go off."

"Nobody goes bird-watching in the dark," the captain said.

"If you set up your hide under cover of darkness, you're concealed by the time the birds wake up. It's the accepted way to do it. Now look, the Home Guard is jolly patriotic and keen and all that, but let's not take it too far. Don't you just have to check my papers and file a report?"

The captain was looking a shade doubtful. "What's in that canvas bag?"