Sensitive signals and urgent messages are usually routed through the G.C.H.Q. complex outside Cheltenham, or one of its many satellites.
From Cheltenham they are passed to the mysterious building known as Century House, or to the Regent's Park Headquarters.
Ciphers for the Foreign Office go only then, not to Whitehall and Parliament Street, but to an unimposing, narrow, four-storey house off Northumberland Avenue.
They are sent by a variety of methods ranging from the humble dispatch rider to teleprinter by land-line, or even through a closed telephone circuit, often linked to a computer modem programmed for deciphering.
If the romantically minded were to imagine that someone with the title of Duty Security Officer, Foreign Office, prowls the great corridors of power with flashlight and uniformed accomplices, they would be wrong. The D.S.O.F.O. does not prowl. He sits in the house off Northumberland Avenue, and his job is to ensure that all ciphers for Foreign Office remain secure and get to the right person. He also deals with a whole mass of restricted information concerning communications from abroad, both from British sources, and from those of foreign powers. Leaders of friendly foreign powers, in particular, look for assistance from the Foreign Office.
They usually find it with the D.S.O.F.O.
It was to the little-noticed turning off Northumberland Avenue that James Bond was now heading in the Mulsanne Turbo.
They had taken him out to the garage shortly after nine-thirty, made sure he had money, credit cards, his ASP, and petrol in the tank.
Holy, Rahani and Zwingli had, in turn, clasped his hand, Zwingli muttering, "Good to have you on the team,' and promptly at nine forty-five the Bentley had eased its bulk on to the gravel turning circle, flashed its lights once, and swept on its stately way, up the drive and on to the road to Banbury.
From Banbury, Bond followed the route they had ordered him to take - straight to the M4 motorway, and so into London.
He did not spot any shadows, but had no doubt that they would be there. It did not worry him. The street where he would finally stop would be cleared of all but authorised vehicles so there was little chance of him being observed once the car had been parked.
Risking the wrath of police patrols, Bond made the journey at high speed. From numerous telltale signs and bumps he was certain Peter Amadeus had managed to let himself into the boot. The little programmer would by now, be suffering considerable discomfort. Bond stopped once, at the service station near Heathrow Airport, to fill the tank. There he was able to let a little air into the boot and to satisfy himself that Amadeus was indeed alive and well. In a whisper, he explained that release just then was impossible, but it would not be long now.
Less than forty minutes later, Amadeus was freed, speechless and stiff from the cramped ride, but all the same duly grateful.
"Well, this is where you show your gratitude." Bond took his arm firmly, leading him towards the lighted doorway of the terraced house.
Swing doors opened on to a marble-tiled hallway with a lift which took them to the second floor and a minuscule landing, watched over by a muscular government messenger, who half rose from his desk to ask what they required.
"Predator,' Bond snapped at him. "Tell them, Predator and friend." He did not smile.
Less than a minute later, they were led quickly through a passage and into a larger room. The red velvet curtains were drawn. A portrait of the Queen hung over the Adam fireplace and another of Winston Churchill adorned the opposite wall. A long gleaming boardroom table occupied a large portion of the available space.
Six faces turned as one. M was at the head with Bill Tanner on his right and another officer Bond recognised to the left. Major Boothroyd, the Armourer, Head of Q Section, sat to Tanner's right with Lady Freddie Fortune next to him.
Bond did not have time to be surprised at Freddie's presence, for the sixth member of the reception committee left her chair almost at a run.
"James, darling. Oh, it's so good to see you.
Percy Proud, oblivious to the officialdom, held him close, as though she would never let go again.
"Commander Bond! Miss Proud!" M was genuinely embarrassed. "I, er, think we have important work to do." He detached himself from Percy, acknowledged the others, and introduced Peter. "I think Dr Amadeus will be able to contribute." Bond kept glancing suspiciously at Freddie Fortune - so often that M finally said, "Lady Freddie's been on the team for some years. Done good work, infiltrating. Sound woman, 007. Very deep cover.
Forget you've ever seen her here." Bond caught Freddie's steady gaze, returning it with a sardonic smile and cocked eyebrow. Then, M drew the conference to order.
"I trust you've gone into Endor, sir " Bond started.
"Yes, 007. Yes, we went in about an hour after you drove out, but the birds had flown. I don't think many were left when you departed.
The rest have vanished into thin air. Bag and baggage. We thought you could tell us - "I'm instructed to return there, by the same route as I came." Bond recalled the deserted feel of the place that morning, and the fact that he had seen only Cindy and the Arab first thing, and Tigerbalm, Holy, Rahani and Zwingli later.
"The cars were there." He felt it was a lame comment.
"Three of them, still in the garage."
"Two when our people arrived." The officer Bond recognised but could not name was obviously running liaison.
"How about my girl? How about Cindy?" Percy touched his sleeve, and Bond could not meet her eyes.
"I'm not certain. She was a great deal of help, last night. Even tried to steal a copy of their main program the simulation of whatever they're doing." He turned to M. "It's on SPECTRE'S instructions, this business, sir, did you know?"
"Is it, indeed?" M could administer the iceberg treatment when he had a mind to. "That villainous outfit is on the warpath again, eh?"
"You still haven't told me about Cindy." Percy had her hand tightly on his arm now.
"Just don't know, Percy. No idea." He told her about the previous night, leaving out all that happened after he got back to her room, but repeating the conversation with Holy in the morning.
"So we have no ideas abut this simulation?" M sucked at his pipe.
"If I could have a word." They all turned towards Amadeus. "I've seen the simulation running. It was a couple of weeks ago. The wee small hours. Couldn't sleep. I went down to the laboratory, and Jason was in what we call the War Room - Mr. Bond knows: it's at the far end.
Jason was engrossed. Just didn't hear me." He passed a hand across his forehead. "That was before all those great oafs - gun-happy boys turned up. Before I got nervous about being there.
M looked uncomfortable, spluttering over his pipe.
"Well, thinks I, have a look, Pete. See what the crooks are after next. They refer to it as the Balloon "The Balloon Game, yes,' Bond interrupted.
"I've seen it and you haven't. I have the floor, Mr. Bond, please." He looked around him revelling in the attention he was getting. "As I was saying, they call it the Balloon Game, but it's to do with something they've named Operation Down Escalator." M's brow creased as he repeated the words under his breath.
"The simulation - Amadeus raised his voice appears to be set in a commercial airport. Not large.
I didn't recognise it, but that's nothing to go by. The scenario begins in an office complex just to the left of the main terminal building. There's a lot of stuff with cars, and positioning men. As far as I could see, the idea was to lift one man.
"Lift?" M enquired.
"Kidnap, sir,' explained Bond.
Amadeus shot them a glance, then scowled, letting them know he did not like being interrupted. "They lift this chap, and there's a lot of changing around in cars you know, he's taken to one point, then switched to another car.