One Aldwych, an Edwardian grand hotel near Waterloo Bridge, is serving a Jimmy Savile tribute tea. It is not explicitly called a Jimmy Savile tribute tea; of course it is not. That would be tasteless, and people would not come to One Aldwych to eat it; it might, in fact, be lucky enough to get a picket, a dazzling marketing dream. No, it is called the Scrumdiddlyumptious Afternoon Tea and it is tied, in sugary, monetised chains, to Charlie and the Chocolate Factory, a musical featuring a man dressed as a Fisher-Price toy (and possible diabetic), child torture and obesity, and explicit abuse of small minority workers, which is playing at the Theatre Royal Drury Lane nearby. (Or as the blurb says: ‘Every item reflects the wit and wonder of Roald Dahl’s classic tale.’ Wit? Really? Surely they mean malice?)

But still this tea looks like the jangling BBC monster, the plastic sociopath in bad clothes. It reeks of candy-stripes and childish terrors and of pederasty; of the horror of ribbons and bells; of the wickedness of soft play centres and turquoise and baby pink; of the evils of sugar, the original and most deadly of all narcotics.

You begin quite calmly, in the huge bright lobby, a banking lobby (formerly Prudential Assurance and Lloyds TSB), with the savouries — excellent sandwiches of salmon and cucumber, a miraculous tart, or flan, of leek and stilton, and tomato. Even so, One Aldwych is sliding into insanity on doughnuts with this one; flowers hang in coloured waves from the ceiling, doing things flowers are not meant to do, and adults (there are no children here) cackle at the food, looking back at desolate childhood years in hunger, or attempt to be macho while drinking a milkshake designed for someone much smaller. Where are the real children? Are they stuck in pipes, or inside TVs, or floating towards the Shard like angry spacehoppers? (Roald Dahl was ever a stranger to psychotherapy.) All is quiet here today in late August, although the Violet Beauregards will arrive in crocodiles at Christmas with their hideous ringlets and soporific daddies — those here, I realise amazed, are having power teas. I imagine David Cameron with Assad, or maybe Arafat with Perez, or Stalin with Tito. Candyfloss is a great leveller. It should feature more in diplomacy.

The staff know this tea is for depraved adults, because they bring us a red cocktail in a Erlenmeyer flask oozing smoke; it is called Cocktail Charlie and it looks like poison. (Cocktails are poison, but they are rarely self-aware enough to come styled as poison. I like this). It is tasteless but pleasing, Dracula vintage 1979, played by Frank Langella with curls and fangs. Then comes the sugar in a delightful tray — candyfloss on sticks, the flavour of which we must guess (‘Mr Assad, is this strawberry or vanilla candyfloss?’), miniature glass bottles of chocolate caramel milk with candy-striped straws, a small pot of Eton Mess and the most marvellous thing I have encountered since I became The Spectator’s restaurant critic, or, in fact, ever — a couture Cadbury Creme Egg. Then there is the cocoa-bean financier, a small chocolate lump cut with edible gold, which is less successful. It looks like Mark Carney’s droppings; if Mark Carney laid a cable in the street, and I am not saying he would, it would look like this. I could not eat it.

Apart from the financier, only the tea itself fails. Sugar can be miraculous and imaginative, but tea should never try to be, being a downer, not an upper, in drug terms. Smooth caramel tea is water that smells of caramel, and it is false. Otherwise, at £29.50 (not including the cocktail) this tea is dark magic; it is horrifying and lecherous and it works. But it is not for children, unless they are mad, or wicked, or dead.