He straightened up and started to make his way forward, moving with his arms wide, keeping his foothold on the wet canvas with difficulty. The barges were close, but there were still several feet of dark, filthy river water between the bow of one and the stern of another. If he fell he would be between the two, and would be crushed long before he could be drowned.

Caleb was on the lead barge, facing him, leaping up and down on the spot in mockery. He put his hands to his mouth to cup the sound.

“Come on!” he yelled. “Come and get me! Come on, Mr. Policeman! I killed Angus, didn't I? I destroyed him! He's gone forever! Finished! No more smart clothes, no more virtuous wife by the fireside! No more church on Sunday and `Yes Sir,' `No sir,' `Aren't I a good boy, sir'!” He folded his anus across his chest, flat, hands down, then flung them wide. “Dead!” he cried. “Gone forever! You'll never find him. Nobody'll find him, ever!

Ever!”

Monk started off towards him, floundering on the canvas piles, stumbling and regaining his balance, taking a wild leap across the dark water to the barge ahead, landing splayed and bruised on his hands and knees. He scrambled forward again, oblivious of pain or danger.

The bargee was yelling something but he ignored it.

They had passed the Blackwall entrance to the South Dock. Ahead of them was the Cubitt Town pier, then the curve of the river around the Isle of Dogs.

He could no longer see the lights of Greenwich on the far side. The fog and darkness were closing in. The marshes to the left were a dim outline. There were other boats, but he saw them only from the corner of his eye. He leaped to the front barge just in time to see Caleb apparently overbalance, land on his knees, then disappear over the side. Then he heard his laughter coming up from the water and just as he reached the edge himself, a rowing boat pulled away, one man heaving on the oars, another crouching in the stern, seemingly terrified.

Monk swore savagely. He swung around to the bargee, although even as he did, he knew it was pointless. The man had no way on earth of changing course. The heavily laden barges were tied together and going upstream on the tide.

“Monk!”

Where was the voice coming from?

“Monk! Jump, man!”

Then he saw the second rowing boat with the sergeant and another constable in it. Without a second's hesitation he jumped, landing in it and sending it rocking so violently it all but overturned. The constable at the oars let out an oath. The sergeant grabbed him roughly and forced him down on the duckboards at the bottom, and the boat righted itself and plowed forward again.

“After 'im!” the sergeant shouted unnecessarily.