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But shortly after his son Theo was born in 1960, Dahl sent a revised version of the story, entitled "Charlie's Chocolate Boy" to his agent Mike Watkins, in which the eponymous hero visits the factory with nine other children and is accidentally made into a chocolate figure and delivered to Mr Wonka's house, where he foils a burglary and is rewarded with a sweet shop of his own "nine storeys high".

The others include Augustus Pottle (Gloop's precursor), Miranda Grope (disappears up the pipe with Augustus), Wilbur Rice, Tommy Troutbeck (whose fates you will learn in the never-before-published chapter cut from the draft that accompanies this piece); Violet Strabismus (had been Glockenberry, would become Beauregarde, always ends up violet); Clarence Crump, Bertie Upside, Trevor Roper (who all overheat after ingesting an unwise number of Warming Candies), and Elvira Entwhistle (gets booted down a rubbish chute but would eventually be known as Veruca Salt as she went) – an unwieldy group and it is obvious that some of them need to go, but it is still great fun while they're around.

But then Theo was almost killed when a cab hit his pram in New York. He survived, but developed hydrocephalus. The shunt put in his head to drain the fluid kept clogging, nearly killing him each time. Dahl mined Theo's neurosurgeon Kenneth Till for every ounce of his knowledge then took the problem to his friend Stanley Wade who, in a twist you wouldn't dare write, was an engineer whose hobby was making miniature engines for toy aeroplanes and whose job was running a factory that produced precision hydraulic pumps.

Together, the three men invented the Wade-Dahl-Till valve for Theo and the thousands of other children in his situation. In June 1962, the first one was inserted into the head of a patient in London's Great Ormond Street hospital. It worked beautifully. Theo was well enough not to need it by then, but over the years it was used to treat thousands of children all over the world.