There was no one to see them off but Lightfinger and he watched the boat edge slowly round the stern of The Ethel Ada like a huge insect with only four legs. Darkness covered the craft and soon Lightfinger could only hear the voice of Napoleon saying gently, "Paddle, stroke side, ease up, bow. Hands on the gunwale, number five. Forward all." When Lightfinger could hear no more he turned and walked quickly away, glad to have nothing to do with the gloomy and dangerous Thames.

The Silver Belle Flower crept out until she was well clear of the barges moored along the southern bank. Napoleon didn't take her out into midstream; he wanted to be within easy reach of the bank and its complicated blackness, so that if a police launch appeared they could take cover rapidly.

Napoleon let the boat drift round until the bow was pointing just where he wanted it, then he tensed his muscles and gripped the two rudder strings tightly.

"Come forward," he whispered. The crew leaned towards him in their seats. "Paddle," said the navigator and the boat sprang up river, eager to be under way.

Nobody spoke except Napoleon, there was too much work to be done to allow conversation. Every rower was concentrating his whole body, every bit of his brain, on handling his oar as cleanly as possible.

The water surged below the boat and lifted it regularly, trying to bear it backwards and down to the sea. Occasionally a dark mass of barges, lashed together into one rigid floating world, slid by them, towed or pushed by a small tug. Mysterious lights coasted by and men with deep voices called out to one another, and from either shore came the distant groan of traffic, trapped in the streets. It was nearly midnight now, but, small and fearful on the Thames, the Borribles soon lost the sense of time and place.

Gradually, as the rowers came more and more together, a feeling of exhilaration passed from one to the other and their handling of the boat improved. Napoleon, who had never been on the river before, let alone in command of his own ship, was bursting with gratification and fulfilment. He could have sailed for ever.

But the swift tide was against them and it took most of their effort to stay in the same place. There was no ornamental pleasure lake beneath them now but a sinuous monster with rolling ropes of muscle that could shatter a boat like a walnut caught in the crook of a navvy's arm.

They clawed their way forward, away from Battersea Church and up to Ransome's Dock, where Eaton House and Archer House stood behind the green of a narrow strip of recreation ground at the end of Battersea High Street. Underneath the grey-painted girders of Battersea Railway Bridge it was blacker than black and they felt insignificant and frightened, but Napoleon kept them rowing, exerting their small muscles to the uttermost. To the north were Chelsea Creek and the LTE Generating Station. Far ahead, glowing crimson in the night sky, at the end of Battersea Reach, was the Fulham Power Station, a beacon for the night's work.

Napoleon watched his crew carefully, determined not to overtire them, and before long he decided to take cover and let the Borribles rest and maybe eat something from the rations that had been stowed aboard the previous day. His instructions came clearly and the boat slipped into the southern shore and came to a halt between two enormous barges.

"Ship your oars," commanded Napoleon and he went bounding over the benches to tie the boat's painter to a cable which ran from one of the barges to a huge buoy. The Borribles broke into the food and began to congratulate each other, pleased with their progress. "Well," said Napoleon, coming back to face Knocker, anger in his voice, "how'd you manage to fiddle it?"

The attention of the others was caught by the question. They too wondered how Knocker had managed to get himself included in the expedition.

"I'm not here as a member," said Knocker, looking behind him at the curious Borribles, and feeling it was only right that he should explain. "There is in the Rules a provision for exceptional Adventures which allows an Observer-Historian to go along and record it all. Spiff asked me to come, at the very last moment, that's all. I couldn't refuse really—not that I wanted to."

Orococco beamed. "I'm glad, pleased to see you with us."

"Yeah," said Vulge, "you know all about parks and countryside and that."

Everyone else nodded and Knocker felt it was going to be all right, but Napoleon said: "We'd better get one thing quite clear, Knocker, your status as instructor is over, you don't give any orders, see. All decisions will be arrived at jointly. You don't change that."

"No, of course not," Knocker assured them all. "I won't even give my opinion unless you ask for it. I can't even take part in the Adventure until you've finished, though I can use my catapult in self-defence."

"All right, that's fair enough," said Napoleon, "long as we've got it quite clear." He thought for a while and when the others were not listening he leaned close to Knocker and whispered into his ear." Is that all you've come for, Knocker, just to be an observer?"

Knocker pulled his head back and squinted at the Wendle." I've come for the Adventure, of course, that's all. What other reason could there be?"

"I dunno," said Napoleon, "but there might be something." And he shoved a sandwich into his mouth and still looking at Knocker closely he munched the bread as if he hated it.

They stayed in the dark shadow by the barges for nearly two hours and when they had all eaten and rested and discussed Knocker's arrival Napoleon made them take their places once more, and with gentle sideways strokes they brought the boat out into the river. There was not much of the night left to them and they would need to be well under cover, hidden from inquisitive eyes, before the slightest hint of dawn should appear in the sky.

"We ain't going much further," said Napoleon, "then we'll have to find some more barges to hide amongst, along by Fulham Power Station."

They rowed on. Several large shapes passed dangerously close and The Silver Belle Flower rocked badly enough to ship a little water, but nobody noticed the Borribles and not once did they see a police launch. Napoleon peered into the darkness, his eyes keen and narrow, like some mariner of the high seas, searching for a hideout. Just before dawn he spied what he had been waiting for, a cluster of four or five barges, moored below the low tide mark, and in the middle of them, he hoped, a space of calm water, large enough to hide in during the coming day. After that a little more rowing would put them at the mouth of the Wandle where they could conceal the boat and begin their long trek overland.

Napoleon steered the boat across the tide.

"One last good pull," said the navigator, "and then we can rest."

The Borribles worked with a will and they shot across the river, the greasy waves knocking roughly at the boat.

"Keep pulling," shouted Napoleon. "One two, one two." With a sharp tug on the rudder strings he pointed the boat straight at the dark mass, his eyes finding the gap he sought between the barges.

"Ship yer oars."

The rowers obeyed with relief and The Silver Belle Flower sailed silently and gracefully into a little haven of steady water and Napoleon secured the boat fore and aft.

"How do you think we've done then?" asked Stonks massaging his biceps.

"Very good," said Napoleon. "We can rest here all day today, and half of tonight. We've only got to get under Wandsworth Bridge and go a bit further along and we'll be there."

It was decided to leave two Borribles as lookouts while the others slept. Knocker volunteered for the first watch, and Orococco stood with him. The rest of the crew unrolled their sleeping-bags and curled up as best they could in the bottom of the boat.

Knocker kept his watch looking down the grey dawn of the river. Orococco stared upstream and hummed a song, a sad song, and Knocker felt wiser and bigger in himself as he listened, even though the song was sad.

The Thames was busy now. The two lookouts could hear the sound of hooting tugs and the swish and the slap of the wash thrown up by passing barges, low in the water, nearly sinking under the weight of tons and tons of cargo: coal for the power stations and containers bound for the London Docks.

The first hour of the watch soon passed and Knocker was beginning to feel sleepy when he heard a very slight noise above him on the deck of the nearest barge. He tensed his muscles, slid his catapult from his back pocket and loaded it with a stone from his bandolier. Slowly he stood up and pulled the chunky elastic back so that it was half ready. He glanced quickly up the boat but Orococco was facing the other way, his head nodding. He looked asleep; Knocker waited.

The boat rocked and the Borribles slept on. A scrabbling sound, very cautious, came from above. It seemed to Knocker that someone was trying to find a way out from underneath the tarpaulin that covered the lighter which gave them protection on the shore side. Knocker ran his gaze along the iron wall of the barge, along the criss-cross of ropes that held the tarpaulin down. He could see nothing. Again he looked towards the other end of the boat. Orococco's head still nodded.

The scrabbling noises stopped. Then Knocker heard the noise of a knife making a slit in canvas. He pulled the rubber of his catapult tighter, but as yet he had nothing to aim at. Suddenly there was a splitting sound and a small figure dressed in green and brown burst into view on the very edge of the barge right above The Silver Belle Flower. Whoever it was had his back towards Knocker, who, aiming for the kidneys, pulled the catapult to its full extent and let fly. He heard a pained intake of breath and the intruder teetered back and forth as if he could not decide which way to fall. At that moment Orococco turned, his catapult in his hand. He had been feigning sleep, only waiting for the unseen enemy to appear. He took in the situation, saw the target and fired, but luckily, as it proved, he missed. As Orococco's stone sped from his catapult the newcomer lost his balance and fell headlong and heavily into the boatload of Borribles, landing in a crumpled heap between Knocker and the first seat. Knocker threw down his catapult and leapt on the interloper, holding him down while Orococco stumbled over the sleeping forms of his companions to give assistance.