Not as cute as the clockwork toy that inspired his 1967 classic children’s novel The Mouse and his Child. Not as amusing as the collection of ornamental frogs, from the kitsch blow-up model to the svelte specimen in Hungarian glass.

But the turn-of-the-century painting by Andrew Hislop RA, bought for under Pounds 20 round the corner from the writer’s house in a Fulham terrace, has earned its place in the Aladdin’s cave crammed with the reminders of a lifetime’s writing picture books, children’s stories, poems, plays and eight adult novels, not forgetting Mrs Kong. It is the gateway to a literary landscape on a par with Narnia or Wonderland. Hoban’s map of mind games is the basis for The Trokeville Way, his first full-length novel for children since The Mouse and his Child, which cast wind-up creatures in an epic tale of survival almost 30 years before Disney’s Toy Story.

The new tale, to be published next month, is pitched at slightly older readers, from 11 to adult. It explores the mes sy emotions of early adolescence, the particular pressures on boys who are teetering on the brink of puberty and the mechanics of the power games and pecking orders that can endure into old age.

Hoban shies away from worthy motives, but adds: “I hope this book will be useful for some boys. A lot of unfinished business from my boyhood carried forward into my grown-up life because I didn’t resolve it when I was a boy.”

Now 71, Hoban has charted his three sons’ progress on “that dark journey of the self from childhood to being grown-up”. The youngest, Wieland, is his model for Nick, the 12-year-old narrator in The Trokeville Way, and it is set in Barnes near St Paul’s School, where they were all pupils. He has encouraged them to keep their “unfinished business” to the minimum. “We have always talked mainly about things we enjoy like music, books and films rather than feelings, but we have talked a lot. I think they’re doing all right.”

He laments the absence of rites of passage from the lives of most modern adolescents in western society, the lack of “a traditional and approved way to making contact with the world of the unseen that lies behind the limited-reality consensus of everyday”.

The Trokeville Way offers Nick a rite of passage, although Hoban is more concerned with telling a powerful story: “I was taken with the idea of a boy on his way home from school getting into a whole world of strangeness.” The mystery that ensnares Nick is likely to capture readers who might otherwise be wary of a novel that takes in the pangs of awakening sexuality and the tragedies of lost youth and dashed hopes.

Nick’s “whole world of strangeness”, which proves to be inside his own head, is saturated with longing for an elusive ideal with its roots deep in previous generations’ mistakes. The libretto of Mrs Kong makes interesting reading alongside it.

In the preface to the libretto, Hoban describes his attempts to track down the original of “Girl With a Pearl Earring” (the source for the character of Pearl, the second Mrs Kong), and his discovery after an overnight journey to The Hague that the painting was in New York. This frustrated quest, he wrote, represented “a reminder of the discontinuity of image”. Nick’s glimpses of a mysterious girl in white, “always partly now and partly remembered”, have a similar quality. The misunderstood monster Kong, too, is described in the libretto as “a little never was there”. Hoban calls him “the lost and lonely child of all the world”. Fremder, the intergalactic wanderer in Hoban’s latest adult novel, seems to share this role, as does the hero of The Trokeville Way.

Nick’s greatest challenge in store is conquering his fear not easy at the awkward age of uncertainty. He is unsure of his own strength, unsure whether he prefers Bart“k or heavy metal or whether fantasies about his friend’s sister (an unattainable older woman of 14) are really more interesting than playing conkers. While his father preaches interest rates and his big brother preaches Marxism, Nick still has nothing to sound off about.

He has grown out of the “low and muddy fooling around and high and wobbly fooling around” indulged in by Tom in Hoban’s Captain Najork stories, but has not yet found something to replace it with. Some of his pursuits are timeless, like his chess and his tussles with Harry Buncher (not so much a bully as a slightly older boy with a bit more bravado and testosterone).

An action-and-adventure element is supplied by the treacherous terrain with its slimy, stinking river, its deformed, polluted wood and its eerie earthwork. Nick, pursued by Buncher and crossing paths with other familiar figures, stumbles into the hazards of the mindscape after an encounter with a redundant magician. “What I particularly enjoyed in writing this is that there’s no magic [the magician is called Moe Nagic],” says Hoban. “It’s a mind trip. Nick’s at the mercy of his mind.”

The passage to Trokeville opens when Nick buys a peculiar jigsaw puzzle from Moe Nagic hence the Hislop watercolour. “I just made the picture a bit more so,” said Hoban. “I liked the nondescript figures on the bridge and the three trees like girls coming down for a swim. The idea of getting into a picture has always fascinated me.”

His first career was as an illustrator and, he remembers, “There was an expectation in my family that I would be a famous artist because I could draw very well from the age of five. I staggered around under that burden until I left high school.”

His Russian-Jewish parents came to the United States in the 1900s, “an era of very energetic self-improvement and big hopes for their children”. His father, who later became a newspaper advertising manager, went to college at night and called his son Russell Conwell after a lecturer he admired.

He grew up near Philadelphia, reading Oscar Wilde’s fairy tales, which he remembers with a painter’s sensibility. “There was so much colour and light and shape in them . . . as strange and fantastic as the stories are, they seemed to be full of essential truths. ‘The Fisherman and his Soul’ in particular made a profound impression on me.”

He has never regretted the transition to writing, which started with picture books in the 1960s. His Frances series, the tales of the sparky singing badger illustrated by his first wife Lillian, ensured his success and have had a continual following.

“When I used to paint I rated myself on a scale from zero to Rembrandt but writing is different how I write is how I write and I don’t have to compare myself with anyone, I just do it. Even when I get stuck and it’s really hard slog, it’s never a burden. It has always been full of the illicit joy of doing what I want.”

The philosophy that drives his writing is echoed in Nick’s debates with his inner self. As in much of Hoban’s fiction, the message is: don’t give up, don’t settle for second best, be true to yourself. The greatest peril in Trokeville is the “little would” where resolve goes adrift and good intentions come to naught. The account of Nick lost in the “little would”, gathering his strength to confront Buncher, is the most moving passage in the book.

“I was never any good at confrontations, as a boy or a man,” Hoban says. “There was a boy who bullied me at school and I didn’t deal with it well. In writing this I was trying to get as far into that matter as I could. At the same time I was writing Fremder, in which a lot of the same issues are addressed.”

Unlike many fictional treatments of bullying, The Trokeville Way sees Nick and Buncher leaving their differences realistically unresolved. They do not become best friends, or call in the school counsellor they simply ignore each other. Nick, whose character is based on Hoban’s son Wieland, is very much a real boy ask his father.

The Trokeville Way will be published next month by Jonathan Cape