"You're quite a pair." Godliman said.

"You married. Percy?" Bloggs asked.

"I'm a widower."

"Sorry."

"My wife died of tuberculosis in 1930. We never had any children."

"We're not having any yet," Bloggs said. "Not while the world's in this state."

Christine said: "Oh, Fred, he's not interested in that!" Shs went out to the kitchen.

They sat around a square table in the canter of the room to eat. Godliman was touched by this couple and the domestic scene, and found himself thinking of his Eleanor. That was unusual; he had been immune to sentiment for some years. Perhaps the nerves were coming alive again, at last. War did funny things.

Christine's cooking was truly awful. The sausages were burned. Bloggs drowned his meal in tomato ketchup and Godliman cheerfully followed suit.

When they got back to Whitehall Bloggs showed Godliman the file on unidentified enemy agents thought still to be operating in Britain.

There were three sources of information about such people. The first was the immigration records of the Home Office. Passport control had long been an arm of Military Intelligence, and there was a list going back to the last war of aliens who had entered the country but had not left or been accounted for in other ways, such as death or naturalisation. At the outbreak of war they had all gone before tribunals that classified them in three groups. At first only "A" class aliens were interned; but by July of 1940, after some scaremongering by Fleet Street, the "B" and "C" classes were taken out of circulation. There was a small number of immigrants who could not be located, and it was a fair amgumption that some of them were spies. Their papers were in Bloggs' file.

The second source was wireless transmissions. Section C of MI8 patrolled the airwaves nightly, recorded everything they did not know for certain to be theirs, and passed it to the Government Code and Cipher School. This outfit, which had recently been moved from London's Berkeley Street to a country house at Bletchley Park, was not a school at all but a collection of chess champions, musicians, mathematicians, and crossword puzzle enthusiasts dedicated to the belief that if a man could invent a code a man could crack it. Signals originating in the British Isles that could not be accounted for by any of the Services were assumed to be messages from spies. The decoded messages were in Bloggs' file.

Finally there were the double agents, but their value was largely hoped-for rather than actual. Messages to them from the Abwehr had warned of several incoming agents, and had given away one resident spy-Mrs Matilda Krafft of Bournemouth. who had sent money to Snow by post and was subsequently incarcerated in Holloway prison. But the doubles had not been able to reveal the identity or locations of the kind of quietly effective professional spies most valuable to a secret intelligence service. No one doubted that there were such people. There were clues someone, for example, had brought Snow's transmitter over from Germany and deposited it in the cloakroom at Victoria Station for him to collect. But either the Abwehr or the spies themselves were too cautious to be caught by the doubles. However the clues were in Bloggs' file.

Other sources were being developed: the experts were working to improve methods of triangulation (the directional pin-pointing of radio transmitters); and MI6 were trying to rebuild the networks of agents in Europe that had sunk beneath the tidal wave of Hitler's armies. What little information there was was in Bloggs' file. "It can be infuriating at times," he told Godliman. "Look at this."

He took from the file a long radio intercept about British plans for an expeditionary force for Finland. "This was picked up early in the year. The information is impeccable. They were trying to get a fix on him when he broke off in the middle, for no apparent reason. Perhaps he was interrupted. He resumed a few minutes later, but he was off the air again before our people had a chance to plug in."

Godliman said, "What's this 'Regards to Willi'?"

"Now, that's important," said Bloggs. He was getting enthusiastic. "Here's a scrap of another message, quite recent. Look: 'Regards to Willi.' This time there was a reply. He's addressed as 'Die Nadel'."

"The Needle."

"This one's a pro. Look at his message: terse, economical, but detailed and completely unambiguous."

Godliman studied the fragment of the second message. "It appears to be about the effects of the bombing."

"He's obviously toured the East End. A pro, a pro."

"What else do we know about Die Nadel?"

Bloggs' expression of youthful eagerness collapsed. "That's it, I'm afraid."

"His code name is Die Nadel, he signs off 'Regards to Willi,' and he has good information and that's it?"

"'Fraid so."

Godliman sat on the edge of the desk and stared out of the window. On the wall of the opposite building, underneath an ornate window sill, he could see the nest of a house-marten. "On that basis, what chance have we of catching him?"

Bloggs shrugged. "On that basis, none at all."

It is for places like this that the word "bleak" has been invented.

The island is a J-shaped lump of rock rising sullenly out of the North Sea. It lies on the map like the top half of a broken cane, parallel with the Equator but a long, long way north; its curved handle toward Aberdeen, its broken, jagged stump pointing threateningly at distant Denmark. It is ten miles long.

Around most of its coast the cliffs rise out of the cold sea without the courtesy of a beach. Angered by this rudeness the waves pound on the rock in impotent rage; a ten-thousand-year fit of bad temper that the island ignores with impunity.

In the cup of the J the sea is calmer; there it has provided itself with a more pleasant reception. Its tides have thrown into that cup so much sand and seaweed, driftwood and pebbles and seashells that there is now, between the foot of the cliff and the water's edge, a crescent of something closely resembling dry land, a more-or-less beach.

Each summer the vegetation at the top of the cliff drops a handful of seeds on to the beach, the way a rich man throws loose change to beggars. If the winter is mild and the spring comes early, a few of the seeds take feeble root; but they are never healthy enough to flower themselves and spread their own seeds, so the beach exists from year to year on handouts. On the land itself, the proper land, held out of the sea's reach by the cliffs, green things do grow and multiply. The vegetation is mostly coarse grass, only just good enough to nourish the few bony sheep, but tough enough to bind the topsoil to the island's bedrock. There are some bushes, all thorny, that provide homes for rabbits; and a brave stand of conifers on the leeward slope of the dip at the eastern end.

The higher land is ruled by heather. Every few years the man-yes, there is a man here-sets fire to the heather, and then the grass will grow and the sheep can graze here too; but after a couple of years the heather comes back, God knows from where, and drives the sheep away until the man burns it again.

The rabbits are here because they were born here; the sheep are here because they were brought here; and the man is here to look after the sheep; but the birds are here because they like it. There are hundreds of thousands of them: long-legged rock pipits whistling peep peep peep as they soar and pe-pe-pe-pe as they dive like a Spitfire coming at a Messerschmidt out of the sun; coracrakes, which the man rarely sees, but he knows they are there because their bark keeps him awake at night; ravens and carrion crows and kittiwakes and countless gulls; and a pair of golden eagles that the man shoots at when he sees them, for he knows-regardless of what naturalists and experts from Edinburgh may tell him-that they do prey on live lambs and not just the carcasses of those already dead.