The concentric hooped wooden arches framing the proscenium should give you a clue: made from the barrels scraped during the production process.

There can be few writers of my generation whose ten year-old imaginations were not captured and whose own literary ambitions were not seeded by The Wind in the Willows, Kenneth Grahame’s near-perfect novel of childhood with its themes of friendship, loyalty and duty, its clubbable anthropomorphised animal characters whose shared noble quest transcends differences of species, and the luminous Apollonian beauty of the secret heart of the book, a chapter entitled ‘The Piper at the Gates of Dawn‘.

It is therefore not just – as Prince Charles observed of the extension to the National Gallery – like seeing a carbuncle upon the face of a much loved friend, but more tantamount to watching the face of that beloved storytelling friend slammed repeatedly into a rough wall by the crassness visited upon Grahame’s gentle, period, pastoral work by the current creative team, most notably Lord Julian Fellowes whose deadly Downtoned fingerprints are all over the book of this crime against literature.

Even by the standards of years of Christmas musical productions of Toad of Toad Hall, this is expensively vulgar.  Wrongfully engorged to fill the Palladium stage, much has been spent on costumes and publicity but less on sets where the plastic fronds of the willows that grow aslant the river look like they came from a pound shop.  Character has been butchered in commercial pursuit of pantomime: the philosophically minded Water Rat is re-rendered as an estuarian chav, the Weasels are a Momentum-inspired hate mob, and each species is crudely assigned a regional accent to aid differentiation by young audiences, most grating in the lamentable Geordie Mrs Otter of Denise Welch.

Simon Lipkin puts in tremendous effort as Ratty, but doesn’t get the lines or the songs to suit his ability, Craig Mather’s Mole comes closest to the naive innocence of the original, and Neil McDermott’s Chief Weasel is an agile and almost likeable villain.

Grahame’s Mr Toad is a difficult character to redefine: he is intelligent, resourceful and ultimately kindly, although his vanity and foolish pursuit of every new fad confound him at every step.  Obliged to play him as a cartooned buffoon booming constantly at the audience, Rufus Hound flails gamely in outrageous costumes like Michael Ball in Hairspray, but without Ball’s evident enjoyment of the farce; in fact Hound – who showed himself to be a superb physical comedian in Dirty Rotten Scoundrels –  looks like a man who is well aware the material is way beneath his talents.

There are tunes, they sound vaguely familiar and fit the ‘musical theatre’ genre, but it’s astonishing how the creative conspiracy of composers George Stiles and Antony Drewe who with director Rachel Kavanaugh and a book by Fellowes managed to turn Half a Sixpence into a reworked masterpiece, has so signally failed with this project.

At one of the earlier performances, due to a technical difficulty, Rufus Hound filled in with 20 minutes of stand-up comedy, at first with the awkwardness of Cliff Richard singing in the rain at Wimbledon but then holding his audience with tremendous showmanship and skill.

He should have done the whole three hours.

Until 9 September.