A few years ago Beatrix Potter’s use of the word “soporific” in the very first sentence of The Tale of the Flopsy Bunnies was being hotly discussed.Should a projected, post-copyright version of the story simply remove such a long and latinate word? “It sits like a dragon,” some said, “at the very entrance to the story: it puts children off.”

Paul Muldoon, one of our finest poets, is, fortunately, as far as possible from the simplifiers. Two years ago in The Last Thesaurus he picked up children’s delight in the long names of dinosaurs, and ran with it to extraordinary and prodigal effect.

Among that book’s riches is an almost throwaway alphabet of animals. In Muldoon’s new Noctuary Narcissus Batt, a jittery denizen of a house innocent of central heating, jumps nearly out of his skin when a turf falls in his open fire: When I start at a flame I feel such a silly ass.

This remark sparks off the first of an alphabetical succession of acutely word-sensitive creatures. An ass “roars from the chimney-breast”, pointing out that the original meaning of “silly” is “blessed”: “That’s the bee in my bonnet” she says. And so a bee blusters in . . .

The wordplay is dazzling, taxing, full of puns and sounds and recondite references. Each creature is disputatious and distinct, and Muldoon raids the word-hoard from slang to latinate to pure Anglo-Saxon in order to cue the next animal’s vociferous entrance.

This is a tougher, darker, drier book than The Last Thesaurus. The “Colossal Glossary” Muldoon thoughtfully provided at the end of the earlier book has grown out of its own skin, and into an even more dazzling poem for children who simply rejoice in words, and do not always want simplicity. Its taxing text is complemented and enriched by the distinguished Czech illustrator Marketa Prachaticka, whose Alice in Wonderland recently won the Premio Grafico at Bologna. Her creatures are as resonant and darkly playful as Muldoon’s stanzas, and as well-matched to the new poem as Rodney Rigby’s rather more cuddly dinosaurs were to the poet’s lighter Last Thesaurus. Faber is to be congratulated for this startling and elegant addition to its Children’s Poetry series. The Noctuary of Narcissus Batt is a difficult, necessary book.

Dibby Dubby Dhu, Elspeth Barker’s selection from George Barker’s poems for children, is another necessary volume in the same series, with its own dark challenges, but with a wider reach of song and sheer fantasy to leaven it. Dibby Dubby Dhu is, Elspeth tells us, George’s “alter ego, anarchic and protean as his creator”.

He is international spy, skipper, castaway, cowboy, magician, and astronaut, a “Pilot of the Outer Spaces”. It is in the non-Dhu poems of the selection, however, the less heroic and strutting ones, that Barker’s range and depth as a poet show to advantage. He writes of the sea, in particular, so magically: its monsters, its mermaids and mermen, its drownings and ice-bound polar islands. He celebrates real, outrageous mischief, and then can turn in a trice to a mood of melancholy: To me, sometimes, it seems as though I walked a world comprised of snow as cheerlessly I have to put one foot before the other foot...

For above all, Barker is, as all true poets are, a truth-teller as well as a spinner of yarns. To finish, the shortest poem in the book: The Cow she is the Queen of Cud.

The Pig he is the King of Mud.

Who are their Princes of the Blood?

The Princes are the little cows And little pigs whose blood will souse The Butcher in his Slaughter- house.