They trooped down a wide row of steps towards the iron gates, DogNut and Courtney leading the way. Behind them came Al and Jessica with Olivia and Finn; bringing up the rear were Marco and Felix, seemingly the only two glad to be getting out of here. They hadn’t come along on the expedition to listen to a lot of chat and watch a bunch of snotty kids pretend they were the government. They wanted to explore and chase sickos and fight and have some good stories to take back with them.

At the Tower Jordan Hordern made them all do two hours’ military training every day, but they hardly ever got the chance to use any of their combat skills. Most of the sickos had been cleared out of the area around the Tower, apart from the no-go zone, of course.

But the thing about a no-go zone was that you never went there. That was the whole point.

A scruffy boy wearing a tall blue policeman’s helmet was waiting to let them out. The helmet was way too big for him and it hung down over his eyes, his hair sticking out untidily at the back and sides. He was nervously tapping his leg with a truncheon and as he saw the boat crew approaching he unlocked the gate and swung it open.

‘I like your helmet, boydem,’ said Marco, ‘but it don’t fit you too good.’

‘It’s not as cool as yours,’ the kid replied.

Marco was wearing a First World War German helmet with a spike in the top. As much for show as for protection. He’d found it at the Imperial War Museum and was never without it.

‘Ta,’ he said. ‘It’s a real babe magnet.’

‘Is it?’

‘What do you think? Has a girl ever said to you she really likes a man in a stupid helmet?’

‘Guess not. But there’s a joke in there somewhere.’

‘Save it.’

The boy was about to say something else when there was a sudden movement and he fell back.

DogNut stiffened like a hound spotting a rival.

‘What is it?’ asked Courtney.

A group of kids had appeared from a nearby hiding-place. They rushed the gates and barged past the kid in the helmet, throwing him to the ground. They were a dirty, mean-looking bunch, armed with metal bars.

They stopped when they saw DogNut’s crew. Getting the measure of them. Their leader stepped forward.

‘All right?’ he said. ‘We come to collect our tax.’

He had a dirty bandanna tied round his head, and wore a shirt with the sleeves cut off, long shorts and heavy boots with no socks. He was casually dangling a machete from a leather-gloved hand. His arms were lean and suntanned. He had the look of someone who had been living rough on the streets.

DogNut sniffed and stepped towards him.

‘You got something to say?’ said the kid with the bandanna.

‘This ain’t my beef,’ said DogNut.

The boy in the policeman’s helmet struggled to his feet.

‘Why don’t you all sod off?’ he said, and one of the marauders knocked his helmet off, then, as he bent over to pick it up, booted him in the backside, sending him sprawling into the iron railings.

‘Leave him alone,’ said DogNut.

‘Thought you said this wasn’t your argument,’ said Bandanna.

‘It will be if you keep dumping on that kid.’

Bandanna gave a little nod to one of his friends who gave the poor kid in the helmet a vicious whack in the side with his club. The kid groaned and curled up on the ground.

‘Don’t get involved,’ Courtney hissed at DogNut.

‘I am involved,’ he replied, and now it was his turn to nod at his team. Marco, Felix and Ugly Al came forward. Marco carried a short spear, Felix had a sword and Al was armed with a heavy mace. There were five guys with Bandanna, so he had a numerical advantage. It was clear, though, that if there was a fight it would be bloody. Someone could easily wind up dead. It wasn’t a risk any of them wanted to take. They stood there, taunting each other, hurling insults, and in the end DogNut went toe-to-toe with Bandanna. Their faces millimetres apart.

‘We’ll take you down, you skonky ratburger!’ DogNut yelled.

‘Yeah, well, I’ll cut you first.’

‘Pretty tough with that chopper in your fist, ain’t you?’

‘All right!’ Bandanna dropped the machete and threw his arms wide. ‘You want some of me? Come on then! Take it!’

DogNut couldn’t believe the guy was being so stupid and quickly punched him hard in the throat before he had a chance to defend himself. Bandanna gasped and collapsed. The Good, the Bad and the Ugly saw their opening and rushed forward, crowding the rest of the gang out. Then, with threats and shoves and raised weapons, they hustled them through the gate, two of the intruders holding up Bandanna, who was struggling to breathe.

As they retreated down the road, DogNut picked up the machete and hurled it after them.

‘Take your pencil sharpener with you!’ he shouted, and laughed as they danced out of the way of the whirling blade. Bandanna wrenched himself from the hands of his friends and croaked hoarsely at DogNut.

‘You shouldn’t of done that. We’ll be back. And there’ll be more of us next time. The taxes have just gone up!’

‘Yeah? Tax my arse!’ DogNut shouted, and waggled his rear at them.

They helped the local kid to his feet and he straightened his helmet, thanking them over and over.

‘Who were they?’ Courtney asked.

‘Kids from the park,’ said the boy. ‘They’re raiding us more and more lately. They wait for an opening then steam in. I thought it was all clear, but they must have been hiding behind one of the old security barriers. Basically they get inside and try to get hold of food and stuff. The kid you punched out’s called Carl, one of their gang leaders. I guess I owe you one.’

‘Save it,’ said DogNut. ‘You want to help us you can tell us the best way to Buckingham Palace.’

The boy scratched an armpit and pointed with his truncheon.

‘Across the square and straight up Birdcage Walk. That’s the way I’d go.’

‘Cheers.’

‘You’d have to be stupid to go my way, though,’ the boy added.

‘Why’s that?’

‘Cos Birdcage Walk runs along next to St James’s Park, which is where your new best mate, Carl, and his crew came from.’

‘So why’d you say you’d go that way, then?’ DogNut asked.

The boy made a dismissive farting sound with his lips. ‘Dunno. I always get things wrong on behalf of I’m a bit thick.’

‘What’s your name?’ Courtney asked him.

‘My mates call me Bozo.’

‘Why that?’

‘Told you. Cos I’m a idiot.’ Bozo hit his helmet with the truncheon, hard enough for it to make a loud thwack. He went cross-eyed.

DogNut pressed him. ‘Do you want to tell us the best way or not?’

‘If you were cleverer than me you’d go up Victoria Road and swing round to hit the palace from the side. Is a bit further, but you’d avoid the mugs in the park.’

‘We’ll go the clever way then,’ said DogNut.

‘Thought you might,’ said Bozo. ‘But be careful. I was at the palace before I came here. David’s bad news. He’s a creep. He don’t like anyone to disagree with him. Keeps everything locked down. It was well hard to get away, I can tell you. And he keeps trying to get children from here to go and join him. You know, like Facebook? Everyone used to try and have the most friends. It’s like that. He wants the most followers.’

‘Kids like David don’t bother us,’ said DogNut, leading his gang out of the gate. ‘We’ll be fine.’

Bozo saluted them and wished them luck.

‘Dick,’ said Felix as they marched off across the road. DogNut laughed and led them round the great bulk of Westminster Abbey and on to Victoria Street, the wide road on the other side. They kept to the middle and formed into a loose bunch, with nobody really taking the lead. None of them seemed to want to be the one out in front.

Marco and Felix were the most relaxed, they chatted to Finn, who carried Olivia on his shoulders.

‘What did you reckon to the talent back there?’ Felix asked.