Within.666 of a second they had done with their main course and were seeking a mangey-looking half-terrier for afters. The read-out which followed, had it been broadcast in standard five-point lettering, would have formed an equation sufficient to engirdle the Earth several times around. Summing up, the computer pronounced Old Pete a harmless loony and no threat to security. It did, however, suggest that certain discrepancies existed regarding multiple payment of pensions in the past and that the data relating to this would require a prolonged period to assess accurately. It refused to comment on Young Chips, offering only a cryptic remark that the wearing of flea collars should be made compulsory.

Old Pete finally gave up his unequeal struggle and limped off down the street effing and blinding for all he was worth. Young Chips lifted his furry leg contemptuously on to the dull black-glass wall and skipped off after his master. The Lateinos and Romiith mainframe filed away Old Pete’s vitals and beamed a triplicate copy of the now completed programme to the bio-gene constructional workshop, twenty-six storeys below. The probe moved up once more to the building’s roof and turned itself to more pressing business. Included amongst a billion or so other tiny matters which required attention was the removal from this plane of existence of a certain local Professor and his unclassifiable house-guest.

The sensory scanner criss-crossed the triangle of streets and houses, prying and probing. The X-ray eye of the great machine penetrated each dwelling, highlighting the plumbing pipes and television tubes. The house-owners were tiny red blotches moving to and fro, going about their business unaware that all was revealed to the voyeurist machine which lurked above their heads. The data whirred into the computer banks, but at intervals the motors flicked and whined as a patch of impenetrable white light appeared on the screen. As the macroscope focused upon the area of disturbance and intensified its gaze, the area revealed itself to be a large house and garden set upon the historic Butts Estate. The data retrieval cross-locators coughed and spluttered, fruitlessly seeking a snippet of relevant information, but none was to be found. The white patch glared on the screen, the missing piece of a great jigsaw. The best the print-out could come up with was “Insufficient data, scan penetration negative, over-ride and re-submit.”

Professor Slocombe rewound the great ormulu mantel-clock and, withdrawing the fretted key from the gilded face, set the pendulum in motion. The sonorous tocking of the magnificent timepiece returned the heartbeat once more to the silent house.

Sherlock Holmes entered the study through the open French windows. “It has stopped again?” said he.

The Professor nodded sombrely. “The mechanism has become infected, I believe.”

Holmes slumped into a fireside chair. “You have had the electricity disconnected, I trust?”

“As we discussed, we will have to be very much upon our guard from now on. I have taken what protective measures I can, but my powers are not inexhaustible, I can feel the pressure upon me even now.”

Holmes slid a pale hand about the decanter’s neck and poured himself a small scotch. “I have just spent a most informative hour with Norman Hartnell. A man of exceptional capability.”

Professor Slocombe smiled ruefully. “He keeps us all guessing, that is for certain.”

“I discovered the hand of a duplicate replacement at work in his shop and sought to question it.”

Professor Slocombe raised his eyebrows in horror. “That was a somewhat reckless move upon your part.”

“Perhaps, but when confronted by the gun you gave me, the thing took flight, literally, through the ceiling of the shop. To my astonishment the real Mr Hartnell appears from his quarters. The mechanical double was, in fact, something of his own creation. To spare his time for more important matters, according to himself.”

Professor Slocombe chuckled loudly. “Bravo, Norman,” he said. “The shopkeeper does have something rather substantial on the go at the present time. It is of the utmost importance that nothing stand in his way.”

Sherlock Holmes shook his head. “Your corner-shopkeeper produces an all-but-perfect facsimile of himself with no more than a few discarded wireless-set parts and something he calls Meccano and you treat it as if it were an everyday affair.”

“This is Brentford. Norman’s ingenuity is not unknown to me.”

“And do you know how his mechanical man is powered?”

“Knowing Norman, it probably has a key in its back or runs upon steam.”

“On the contrary,” said Sherlock Holmes, taking the opportunity to spring from his chair and take up a striking pose against the mantelpiece, “it runs from a slim brass wheel set into its chest. Your shopkeeper has rediscovered the secret of perpetual motion.”

“Has he, be damned?” The Professor bit upon his lower lip. “Now that is another matter entirely.”

“Ha,” said Holmes, nodding his head, “and now would you like me to bring you the automaton, that you might inspect his workings at first hand?”

“Very much. Do you consider that such might be achieved in safety?”

“Certainly, I took the liberty of following the ample trail he left, after my interview with Norman. He is holed up on the allotment.”

“Holed up?”

“Certainly, in Mr Omally’s shed. If I can catch him unawares I shall bring him here at gunpoint. Although I must confess to a certain bafflement here. How might it be that an automaton who can leap without effort or apparent harm through ceilings and walls, fears the simple bullet?”

“Ha, yourself!” said Professor Slocombe. “You have your secrets and I have mine. Go then, with my blessing, but stay upon your guard. Take no unnecessary risks.”

“Natcho,” said Sherlock Holmes, turning as he left to make a gesture which all lovers of the New York television cop genre know to be the “soul fist”.

“Natcho?” Professor Slocombe shook his old head and returned once more to his work.

Having slipped away to Jack Lane’s for a pint or three of non-takeover-brewery beer, Pooley and Omally now loped down a bunting bedecked Sprite Street. To either side, front gardens bulged with sections of the home-made floats destined to join the grand carnival procession of this year’s Festival which, meaningless as it now appeared, showed every sign of going on regardless. Exactly what the theme of the parade was, neither man very much cared. As they ambled along they muttered away to one another in muted, if urgent, tones.

“As I see it,” mumbled John, “we have few options left open to us at present. If the end of civilization is approaching there is little, if anything, we can do about it.”

“But what about all my millions?” Jim complained. “I thought that the holders of the world’s wealth always had it up and away on their hand-mades and sailed their luxury yachts into the sunset at the merest mention of impending doom.”

“What, off down the canal you fancy?”

“Well, somewhere, surely? Let us at least go down with Soap and weather it out until the troubles are over.”

“I had considered that, but you will recall that it is very dark down there in his neck of the woods. And darkness would seem to be the keynote of this whole insane concerto.”

“So what do we do then?”

The two stopped on the corner of Abaddon Street and stood a moment, gazing up at the great black monolith towering above them.

“I have been giving this matter a great deal of thought and I think I have come up with an answer.”

“It better be a goody.”

“It is, but not here. Walls have ears as they say. Let us hasten away to a place of privacy and discuss this matter.”