As Toby Wey approached London in the early hours of April 10th, 1824, the silhouetted spires of the city seemed like so many bony fingers beckoning him towards his doom. With good reason.

Toby was then fourteen years old and, along with the most notorious British criminal of the time, the hideously maimed, psychotically violent “Dog-Face” Jack Shepherd, had just played a key role in a robbery which was as daring as it was bizarre.

It had involved the use of a creature, widely believed to have supernatural powers, known as The Mechanical Turk. Having masterminded the robbery, Jack was now carrying a thousand pounds worth of diamonds stolen from the guests at a stately home in Essex called Hampton Hall.

Or that’s what he believed. In fact there was a secret about the contents of the bag, which only Toby knew. He also knew that, when the bag was opened, the secret would cost him his life. He was, therefore, desperate to get away from Dog Face Jack before this happened.

Which is the reason why, as they rode into the city Toby looked hopefully up at creaking shop signs close above their heads and wondered if he was tall enough to grasp one and pull himself straight up from the horse, with the object of swinging himself from there to a rooftop before Jack to rein in his mount . But the moment Toby began to shift on the crupper, testing the possibility, the robber hissed into his ear. “You’ve got no choice except staying with me. And you know why?”

To make sure Toby was listening, Jack gripped the boy’s earlobe between thumb and forefinger, and Toby felt Jack’s nails almost meeting through the flesh. “Because if anybody finds out what you done in Essex tonight – you’ll swing for it. Just like them.”

And Jack pointed to the iron cages that dangled beside the forest of masts in the River Thames. Inside each was the rotting body of an executed pirate. Toby made no further attempt to escape from the horse, and shortly afterwards they came an area known as Jacob’s Island, where Jack swung them both off, grasped Toby firmly by the shoulder and hustled him down a dark alley.

The alley soon degenerated into a muddy track, which skirted the edge of a stream winding its way down towards the river. The stream stank of raw sewage, which is what it mostly was. They passed a brick archway giving onto a tavern from which came the sound of drunken singing. Then the path became a wooden walkway before degenerating into a slimy flight of rickety steps leading to a wooden bridge over yet another rancid stream. Everywhere Toby saw crumbling tenements behind whose candle-lit window-holes (the glass long being gone) sat dark, motionless figures, lost in misery.

Finally they halted before a pile of rubble where half a building had fallen away.  Toby assumed Jack had taken a wrong turn, but instead he called out “A man’s a man for a’ that!”  There was a pause, and then, without warning, a whole section of brickwork swung back to reveal the entrance to a dark tunnel.

Into which Jack and Toby vanished as if they had never been.

The tunnel was made of brick, dripping with damp, and seemed to go on forever, winding and winding ever deeper into the secret heart of London. Finally, however, it ended in a massive wooden door studded with nails that looked as if they had been made in the Middle Ages. Here Jack repeated the password and when the door opened, Toby’s mouth fell open in sheer astonishment. After the journey he had just undergone he expected the most grim and sordid chamber imaginable.

What he saw was, at first sight, fit for a king.

True, the floorboards were uneven, unreliable and frequently missing, the walls were raw brick, the ceiling long gone and huge beams black with age and riddled with wormholes stretching from side to side of the room – but the furnishings were magnificent.

There were no less than three chandeliers, each blazing with candles, the raw brick walls were broken up by gorgeous medieval tapestries and rich Turkish carpets were scattered haphazardly across the floors. There was a huge carved table in the middle of the room, with a damask cloth, at least ten candelabras, Chinese tureens, Delft plates and masses of silver cutlery.

Only the occupants of the room undermined its grandeur – but they did so with gusto. There were whores, thugs, muggers, burglars and con-men of every description, dressed as if for a fancy dress ball – indeed in a kind of hideous parody of the ball from which Toby had just come, because it was clear none of what they wore really belonged to them.

But it was not the throng of unseemly guests who took Toby’s attention: it was the man who was clearly their host, who rose as they entered the room from his place at the head of the table. Perhaps it was Ecclefechan MacDuff’s red beard that struck Toby first, a beard that looked as if an orange cat had once been flung at his face and somehow stuck there. Or perhaps it was the tartan Tam O’Shanter perched airily atop his red curls. Or the white frill shirt, complete with black velvet waistcoat, the plaid kilt - or the huge basket-handled cutlass that hung from the belt around his waist.

On his feet were the daintiest patent leather dancing pumps imaginable.

“My dears!” said MacDuff in a high-pitched Scottish accent as he strode towards them. “My charming, charming friends come on the night of my birthday to wish me continued youth and beauty. Am I right, Jack? How did you know?”

Jack looked around the room and shook his head. “You never cease to amaze me, you old devil. You’re supposed to be selling all this stuff, ain’t you? Not flauntin’ it?”

“So I am, Jack, so I am. But I am a slave to beauty, and need to hold on to the treasures that pass through my hands for as long as circumstances permit me. Which has never worked to your disadvantage, has it?”

“It‘d better not this time, either,” Jack replied. “Even you don’t see stuff like this very often, I can tell you.” And he thrust the bag into the Scotsman’s hands. Toby’s stomach lurched.

Ecclefechan MacDuff weighed the bag and then looked at Toby. The china-blue eyes seemed to rake right through him.

“You haven’t introduced me to your handsome young friend, Jack.” He said in his high-pitched voice. “Would this be the young gentleman who assisted you in your endeavours?”

“He done the gaff, yes,” said Jack.

The Scot smiled coyly at Toby and took his hand.

“I am honoured to make your acquaintance, Mr …”

“Wey,” said Toby. “Toby Wey.” With Jack there, how could he say otherwise?

“Toby,” said MacDuff, rolling the word around on his tongue. “Toby, I like it.” He let go of Toby’s hand and chucked him under the chin. “I think you and I will be friends, Toby. I think we will become very, very good friends.”

There was a cackle of laughter around the room, but Dogface took no notice.

“Not till you’ve finished the business with me, Jock,” he said. “Empty those jools on the table and tell me what you’ll pay for ‘em and I’ll be on my way.”

MacDuff chuckled. “You are so impatient, Jack, you always were. And I like to make myself wait for my little pleasures. I am VERY eager to run my fingers through these baubles you have brought me, and feast my eyes on their lustre, but I am going to DENY myself that satisfaction until after I have finished my dinner. And I am going to insist on the pleasure of young Toby’s company while I eat it, and on yours too. Come along, Toby, you and I have much to talk about.”

And so saying he put his arm around Toby, pushed a youth in a footman’s outfit off the chair beside his own, and sat Toby down. “Now,” he said, “we will feast together.”

Jack was soon thrusting slices of beef into his mouth and washing them down with beer from silver tankards engraved with ancient family crests. But though he exchanged news of robberies, hangings and imprisonments with the desperadoes around him, to whom he was obviously well known, he never took his eyes off either Toby, MacDuff or the bag of jewels.

MacDuff, on the contrary, appeared to have forgotten all about them. He had eyes only for Toby, and ears only for Toby’s story, and everything Toby told him filled him with the deepest delight, especially the tales of the Mechanical Turk. “Oh, how I long for a mechanical Turk of my own,” he said enigmatically.

And then a young woman got up on the far end of the table and began to dance, and the company began to clap in rhythm with her steps, which were soon accompanied by a great variety of stolen instruments, including an oboe and a harpsichord. After which MacDuff threw a glass of brandy down his throat and stood up to begin reciting poetry in a Scotch accent so thick Toby could not understand a word he said.

And then Jack was right beside them both, breathing beery fumes into MacDuff’s face, and telling him that unless he looked at the sparklers then and then he would take his business elsewhere and the Scot would never know what he might have had the chance of buying. MacDuff looked at Jack as if deciding whether to take offence, and then at the cavorting figures all over the room, and decided he was as bored with them as he was with the sound of his own voice.

“I’ll be impressed, will I, Jack?” he said. “I’ll be filled with joy at the very sight of these items, and be unable to resist pouring golden sovereigns into your grubby hands to reward you for bringing them to me?”

“Yes,” said Jack. “I guarantee it.”

“Very well,” said MacDuff languidly, and with one swift movement emptied the bag on the table in front of him.

As the pile of crude, paste diamonds and pieces of coloured glass in cheap gilt settings mounted up in a little hillock on the tablecloth before him a silence emanated from the Scotsman so profound it spread across the entire room.

MacDuff turned languidly to Jack and shook his head reproachfully.

“Your eye isn’t what it was, dear boy,” he said sadly. “Not what it was at all.”

The explosion of fury that convulsed Jack’s already unattractive features was a sight worth seeing - Toby was not there to see it.

Because at the same instant that the bag had been lifted up to be emptied he had slid down beneath the table and begun crawling rapidly away as fast as his knees would carry him.

And was revealed in an instant as Jack, in a paroxysm of rage, lifted the end of the table and sent it crashing against the wall, covering the floor in broken crockery and bouncing silverware.

As Jack, with a six inch, honed steel razor in hand, leapt down the room at him, Toby turned and ran up the overturned table as if it was a ship’s gangplank. It got him only halfway up the wall, but it was high enough for him.

From here with the energy of sheer terror he leapt for the nearest beam, grasped it and hauled himself up onto it so that he was perched like a squirrel high above the room.

But Jack came up after him, slashing with the razor – and Toby had no option but to leap to the next roofbeam, six feet away. And just made it, his fingernails tearing on the rotten wood.

“Jack, Jack,” called MacDuff. “Calm yourself!” But the disfigured man was beyond calming: he had been robbed, and cheated and humiliated by a mere boy – and in front of everyone who knew him. Only blood would pay for the insult. Quantities of blood.

Heedless of the danger, Jack swung himself up after Toby and landed on the beam at the precise moment Toby realised that the next beam – eight feet off - was too far away for him to jump.

And jumped anyway, because he had no option. And missed.

And fell - into the central chandelier.

“My lights!” yelled MacDuff and the company collapsed into laughter. “That’s my best chandelier!” As Toby he swung back and forward on the light fitting, its half-fallen candles spilling hot wax on the drunken, upturned faces below, Jack sprang spider-like to the nearest beam and began inching towards him.

As the hook to which the chandelier was attached gradually pulled loose from the ancient wood. Toby began to rock back and forward, increasing the swing of the chandelier, wider, wider and then, when the arc was at its greatest extent – swung himself up like an acrobat to the beam furthest from Jack, balanced on it on tiptoe, reached up at the tiles of the roof –

- and began to rip them wildly away one at a time to make a hole through which to thrust himself. Then as Jack gathered himself to leap, Toby grasped the edges of the hole and levered himself straight upward and out into the night air. And found himself looking across at the great dome of St Paul’s Cathedral, its metal sheath glittering dully in the light of an enormous moon.

If Toby had had leisure to take it all in he would have seen a magnificent panorama from where he stood; the silvered river to his left, packed with ships from every sea, ocean, river and inlet in the world, the great bridges over the river, the wonderful churches of Christopher Wren, the brooding Tower of London to the east of him, the proud Houses of Parliament to the west - the whole splendid edifice of history and ambition that was London.

But Toby had no time to contemplate it. What he simply did was scramble onto the ridge of the roof and run.

Within minutes Jack and MacDuff’s associates were coming over the rooftops after him, but by then he was far ahead of them, leaping over wider and wider gaps between the buildings as if he was jumping over puddles. The dense mass of smoking chimneys was like a forest to him, allowing his pursuers to catch only the occasional glimpse of his progress, until he suddenly came to a gap between two buildings with a thin stream running between muddy banks far below him, and took a jump he would never have contemplated in daylight and landed on a steeply sloping roof.

And went right through it.

Into the attic of a private home which had been converted into an establishment known as Warren’s Blacking Factory, the last house on the left on a set of greasy steps leading down to the River Thames, known at the time as Hungerford Stairs.

But before I reveal what happened to Toby in Warren’s Blacking Factory, I should perhaps explain how he got into this predicament in the first place.