The night before Christmas and not a creature stirring, not even a mouse.

And look! Look! At Campden Hill Square. All its tall buildings, its squat chimneys, its green lampposts. And in every single window, in every single house, right up to the sky – is a candle.

Lit.

Twinkling at each other, right around the square. Neighbour to neighbour, house to house. It’s the most magical, beautiful, enchanting sight. And it’s extra special this time around because for the past six years London’s been in a grim wartime blackout, and the candles have stayed unlit. But now the gruelling hardship is over. Finally. The city’s children have returned from their country exile, the heavy curtains have been taken down, the bomb shelters cleared, the toy factories fired up, the train stations returned to their rightful use. So just imagine it, on this night, December 24th, 1945: the light. (And let’s never forget the first time that the people of Campden Hill Square had done this. The reason why. The big hearts, the fierce sense of justice, the tolerance. Way back when the trail was blazed: the lights of kindness and community, no matter who you were or where you’d come from.)

Now look at this: all the angry policemen, specialists roped in from out of town, pulling up in their vans and spilling out. Looking terribly determined in their belted suits and hats, faces grim, batons raised in readiness; they’re going to find this mysterious Reptilarium and shut it down no matter what. Clear it out. Cart the owner away. Grab the children. Entirely dismantle the house. Just like that!

The policemen run up the hill and across the streets, through the snow-wrapped garden, along the icy pavements, up and down and back again. Trying to find a clue, any clue, to this legendary house they’ve just been told is so obvious, so sad and lonely and unloved – and crucially – dark.

But you know what?

They never find it.

Because every single house in the square looks incredibly clean and smart, and every single house has its windows lit.

By candles, twinkling in the frosty quiet.

And every time the police rap on a door and ask about the wild, evil man in their midst who’s putting all their beleaguered lives most terribly at stake, the owners shake their heads and say no, not here, not this square, absolutely not.

And don’t you worry about those four crazy Caddy kids transplanted most cruelly from their beloved house. Oh no. Because you wouldn’t believe it. Every other child in the square has decided to donate one of their own Christmas gifts, from under their own trees. But even more wondrously, every child in the square has decided to be their friend. And most gloriously, there are rather a lot of children who live in Campden Hill Square.

So in the fading light of Christmas Eve four kids from the desert on the bottom of the world end up on all manner of sleds and crates, in the wondrous snow that they’ve never before seen. End up making snowmen and throwing snowballs at just about everyone in sight amid big blousy drops of chilly wet. And that night they excitedly count up a rather obscene amount of Christmas presents, in fact; more than they’ve ever had in their lives. When all they were expecting was mouse-tail spaghetti and dead rats!

And do you know where they place the gifts, in preparation for Christmas morning?

Right under the golden cage of Perdita, who’s looking at all the crazy people in her Reptilarium – especially her Basti, who’s quite suddenly flushed – with those eyes as knowing as a cat’s.

And some of the mothers and the fathers of the square have promised that when Father Christmas comes, later that night, he’ll be directed straight to the Kensington Reptilarium, where – apparently – there are four extremely deserving and helpful and wonderfully kind children, fast asleep. In a bath, a library, and a four-poster bed. Well, they hope. Pin, are you listening? Pin? Pin? No disappearing on us any more, all right? That goes for you, too, Bert.

And the grandest turkey feast is planned for tomorrow. Dinda’s supplying the roast. Guests of honour: four kids. Species: Childus Australis Desertus. Their uncle: the war hero to everyone who’s there. Who’s said, actually, that perhaps he’d like to see a little more of his neighbour now that his world seems to be sorting itself out – it’s a chink of light at last – and it’s spoken with the most beautiful smile they’ve ever seen in their lives.

Also coming: one extremely chuffed Horatio Smythe-Hippet, who’s been assured that all reptiles in the vicinity will be most firmly locked up. He’s to be accompanied by the bewitching and freshly divorced Mrs Henrietta Witchum Maggs. ‘Ahem,’ chuckles Basti, every time it’s mentioned, ‘ahem.’

As well as twenty-five coveted bananas from Charlie Boo’s mysterious contacts – and don’t worry, there are twenty-five more, one for every person who’ll be crammed around his own table at the legendary Bethnal Green Insectarium, for his annual, extremely squashed, but incredibly jolly Christmas feast.

But wait . . . there’s one more thing . . . the most incredible thing of the lot –