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."