The Boggart was a white-haired giant with a lantern jaw and irascible temperament. He spent much of his time pottering about in his garden, leaning on his walking-stick and muttering to himself. Couch grass and birds were his favourite enemies, the former eliciting growls of malicious glee whenever it was spotted, the latter inspiring a fuming rant and excited hobble in the direction of the fruit pecking marauders. His whole garden had been laid out with military precision. At the front, pruned to perfection, a rose bed bordered a bowling green lawn and, at the back, an ornately patterned brick path separated the vegetable plot and fruit cage from a low banked herbaceous border which contained his prize-winning collection of yellow chrysanthemums. Protecting against an invasion from the field was a high wooden fence which ran the whole width of the garden.

Chris and I had been spying on him for months, using camouflage techniques from our sniper manual to avoid detection as we crawled across the field. We knew that he was a German but had yet to prove that he was a covert Nazi bent on overthrowing the British government.

Just before Easter, we had peeked through the wooden panels of the fence to discover the Boggart singing in his greenhouse. His head was swaying rhythmically as he filled seed trays with handfuls of potting compost. At the end of the song, he stepped cautiously over the door sill onto the garden path, brushing his hands against the chest of his tan-coloured overalls.

‘Luftwaffe uniform’.

Chris was whispering as he jotted down this new piece of information in his note-book.

‘I bet he’s got a pair of Flying Boots in his wardrobe.’

The Boggart stretched his arms above his head, breathing in deeply.

‘Was für ein herrlicher Tag!‘

Chris was scribbling again.

‘There, did you hear it? He said something about the Führer.’

I looked through the fence. The Boggart was shielding his eyes and looking into the sky.

‘Sibyl, Sibyl, hier sind sie.‘

We had only seen his wife once before. She was a squat woman with a large rump, bowed legs and bobbed white hair. Dressed in a beige nylon cardigan and tweed skirt, she ambled as quickly as she could round the corner of the house.

‘Dort sind sie.’

The Boggart’s arm shot out beyond his shoulder into the air.

‘Bloody hell, the Nazi salute.’

Sibyl followed suit.

‘That’s both of them.’

She was now clapping her hands in delight.

‘Ja, ja, wunderbar.’

Blinkered by his obsession, Chris had failed to notice the honking skein of geese as it disappeared behind him into the distance. I poked him but he waved me away.

‘Bloody Krauts! We know yer Nazis.’

Chris had blown our cover and was rattling the fence in jingoistic fervour.

‘Lassen Sie mich in Ruhe!‘

The Boggart’s voice boomed out. Seconds later, we could hear him hobbling towards us, slashing through the herbaceous border with his walking stick.

‘Shit, let’s scarper.’

We ran in a panic, stumbling over tussocks of grass and sliding through cow-pats. Panting wildly, we came to rest at Chris’s front gate.

‘I’m gonna tell my dad about this. You tell yours.’

That night I found it difficult to broach the subject. I lay on the floor beneath the dining room table, setting up my collection of miniscule plastic World War II soldiers in serried ranks. With the aid of a magnifying glass, my dad had painted some of them with Para red berets. At the back was a detachment from the Welch Regiment, surrounding a column of R.E.M.E. serviced lorries, bren-gun carriers and 25 pounders. The radio was on and I could hear my dad folding back the next page of his Daily Sketch.

‘You’re quiet, Keith. Everything all right?’

He had given me the opening I had been looking for.

‘Dad, Chris reckons that the tall man, you know, the German down the road, is a Nazi.’

‘Who? Hermann Schuster? He was on our side. He was with the Polish lot when they were dropped over Holland. I’ve told you about Arnhem. Well, he was there. He was lucky to get out alive. Highly decorated for it.’

‘But he’s a German.’

‘Not all Germans were Nazis.’

‘Well, why’s he so nasty to kids?’

‘He’s not that bad, Keith. He just wants to be left alone.’

‘What like Old Man Flynny? I mean, Mr Flynn.’

‘Yeah, you could say that. He lost a lot of his family in the war. Your mum knows. I think it was his parents. Definitely a son.’

When I met Chris the next morning, it was obvious that he had heard the same story.

‘Well, if he’s not a Nazi, he’s still a funny old bugger.’

I nodded my head in agreement.

‘Heh, but guess what?’

‘What?’

‘I’ve got something on his missus.’

‘Like what?’

‘Well, you know she’s called Sibyl. Well, Spinach says that’s another name for a witch.’

‘Never.’

‘Yeah, it’s true. Spinach says Old Pop Williams at school told him. They was doing stories from Roman times.’

‘She’s never a witch.’

‘And yer know what witches do? Eat small children.’

‘Well, I’m not going back to find out.’

‘No chance of that. My dad says it’s best if we keep away from the Boggart. He says we’re trespassing in that field. He reckons that the Boggart’ll have told the police.’

Given such a history, was there any wonder that Eddie’s announcement concerning the horse-chestnut trees had been greeted by a chorus of incredulous gasps?

‘Before you say anything, I’ve got a plan.’

We were ordered to return in ten minutes, wearing our wellies.

‘Right, I’ve got the hammer and socks. Richard, you carry the nails.’

Richard, the same age as Eddie, was our second-in-command. He was a tall, willowy boy with auburn hair, pale skin and an infectious smile.

‘Spinach Juice, the rope; Trev and Paul, the wood; Titch, the binoculars, and Nuts and Bolts, you’re on point duty.’

The plan was to creep along a series of drainage ditches so that we reached the trees without ever having to cross open ground. I was in my element. Ditch walking suited my love of secret places. Having spent hours wading through the whole network, I knew where rats predominated, the best place to catch a grass snake, the deep stretches where you had to climb up onto the bank, how to negotiate your way under each bridge, where to find a moorhen’s nest and which branches of hawthorn you could trust as you picked your way through the shadowy darkness of a hedgerow tunnel. I had soaked countless pairs of socks in my efforts to gain such knowledge.

I lowered myself into the ditch just beyond Old Man Flynny’s place. The glistening pond-weed parted in swirling whirlpools to reveal the thick, black water beneath. Instantly, I could smell the rich odours of decomposition. Rotting leaves, stalks of grass and slimy branches floated to the surface. My feet sank into the spongy bottom and the sides of my wellies collapsed against my calf-muscles in a sudden freezing rush. The water was deep. It had risen to within an inch of the tops of my wellies. I walked forward slowly, knowing that if I pushed too hard the icy bow wave would trickle down my jeans, plastering them against my shins. Experience had taught me to glide each foot forward, keeping my legs robotically straight. The soles of my feet were like highly tuned sensors, testing the bottom for changes in density and depth. I could hear the others dropping into the water behind me.

‘You go on. We’ll catch you up.’

Eddie was still at the top of the bank. His jeans were around his ankles and Titch was yanking them free of his black plimsolls.

‘What’s he doing?’

‘Giving Titch a piggy back.’

Looking like a 1930’s Olympic sprinter, Eddie edged forward, blowing out his cheeks as his bare legs slid into the icy water.

‘Here you go, Titch, tie my jeans around your neck and jump onto my back.’

Without hesitation, Titch sprang from the bank, his arms and legs swinging wildly in front of him. The force of the impact knocked Eddie forward, making his knees buckle. He grasped at the tufts of grass on the opposite bank.

‘Shit. Nettles!’

As if electrocuted, he lurched backwards, Titch clawing at his shoulders in a desperate attempt to avoid contact with the churning water beneath him. Like a bucking broncho, Eddie stumbled and lunged in all directions, his plimsolls slipping and sliding through the mud at the bottom of the ditch. Titch was screaming frantically, grabbing at Eddie’s hair as the jeans around his neck slapped the air and the field binoculars bounced on their strap then whipped violently past his ear.

‘Bloody calm down, Titch.’

Eddie was managing to steady himself. Coming to a trembling standstill, he hitched Titch further up his back. He was facing away from us. His thighs were dotted with pond weed and smeared with fingers of blackened reeds. We could see skid marks on his white pants.

‘I thought we’d had it then. Come on, let’s get going. Nuts and Bolts, you lead the way.’

As we waded forward, I imagined that we were a band of French Resistance fighters, the Maquis, on a secret operation. Titch was a wounded British airman who had to be carried to a safe house.

In the distance, a ship’s horn gave three echoing blasts as it entered the Docks. A flock of seagulls wheeled behind a tractor two fields away. Through the elder bushes on our left, we could hear cows tearing at the grass followed by a methodical munching. Occasionally, a hosing stream of cow shit slapped into the grass. We were having to brush the elder branches away from our faces. Plate-sized flower heads, creamy white and smelling of cat piss, danced back and forth on elastic stems. A bridge was ahead of us, its flaky, orange bricks arching over a cylindrical concrete tunnel. Squatting down and leaning forward, we entered like a troupe of Cossack dancers. (Titch was allowed to belly crawl across the track above and join us on the other side.) The air was fetid. We could hear the echo of scampering rats followed by a series of splashes as they dived into the ditch ahead of us. I scraped my back along the tunnel roof, my hands pressing against the patches of moss and slime at the sides.

‘I can’t see a thing.’

It was Trev’s voice.

‘Stop head-butting my arse.’

‘Sorry.’

Dropping from the concrete into the ditch once more, I shuffled forward then climbed onto the bank to wait for the others. Titch was already there.

‘Here, have a Spangle. I nicked some of my dad’s Old English ones. Not the Pearl Drop. I’m saving that for Spinach.’

After the bridge, we turned left, almost immediately, into an archway of thorn bushes. The thinning blossom on the blackthorn allowed a dappling light to sneak through, but whenever we hit a patch of hawthorn we had to inch forward in virtual darkness. We could smell the cloying sweetness of the may blossom but were left to imagine the profusion of white and pink which drifted like snow on the canopy above us. The cocoon of stillness was only broken by the lapping wash of the waves and the occasional snapping of twigs. At the end of the thorn arch, the banks shallowed out and a rickety fence sloped either side of us towards a watering hole where the cows came down to drink. As we entered sunlight again, a coot skittered away from us, flinging up a spray of surface water, before coming to rest in a swaying clump of reeds. The air hummed and buzzed with insects. A collared dove cooed softly and, above us, the sky was filled with the twittering of house martins. Blackbirds were chuckling and in the distance we could hear the grating chir of a greenfinch.

‘I’ll have to put you down for a minute.’

Eddie lowered Titch onto the bank next to a patch of mauve cuckoo flowers.

‘See what he’s doing.’

Titch crawled up to the fence. Carefully parting the cow parsley, he scanned the field and gardens for any activity.

‘I can just see the washing on the line. That’s all. No sign of the Boggart.’

The watering hole, a confluence of three ditches, was about thirty feet across. The water was clear here and the mud beneath a light brown. Great white sheets of water crowfoot floated on the surface giving way to patches of pale blue water forget-me-not at the edge. Approaching the barbed wire, which spanned the entrance to the watering hole, I knew that the mud could be deceptive and give way at the slightest contact. I had lost more than one welly here. The first time it had happened, I had disappeared up to my waist.

‘Keep to the edge.’

I stamped down on the barbed wire with my welly, pulling another strand level with my chest. Careful to avoid snags, the others limbo-danced their way through the gap. I led them into the mine-field of hoof-holes, squirting water with each tentative search for a foothold. In front of us, a dragonfly hovered above a clump of water-mint, then disappeared in a flash of iridescence.

Entering our final ditch, we began to climb a slight rise and were soon crunching our way through a dry bed of leaves and branches. Tree roots sprang from the banksides and coiled seductively round each other. Within minutes, we had arrived beneath the spreading lower branches of the first horse-chestnut tree. Its massive bole was twisted and gnarled like the hand of an ancient giant. A fan of polished roots snaked out of the dried mud then one by one disappeared underneath a scattering of dried twigs and leaves. Looking up, I followed the towering trunk as it flung out a maze of stout branches which craned upwards before gently slanting down again. Stepping back into the sunlight, I rubbed my eyes. Above me, the dark green foliage of the pyramid was bursting in an explosive carnival of pure white flower-spikes, dotted with crimson and yellow. Petals had showered down and were ringing the tree in a magical circle.

‘Right, Richard, this is your tree. Nuts and Bolts, come over here!’