The Christmas pantomime was the high spot of the year, although Alan himself later recalled of Christmas 'that as a small child I was quite unable to predict when it would fall, I didn't even realise that it came at regular intervals.' Back at dreary Baston Lodge, his head was buried in maps. He asked for an atlas as a birthday present and pored over it by the hour. He also liked recipes and formulae, and wrote down the ingredients for a dock-leaf concoction for the cure of nettle-stings. The only books he had were little nature-study notebooks, supplemented by his mother reading The Pilgrim's Progress aloud. Once she cheated by leaving out a long theological dissertation, but that made him very cross. 'You spoil the whole thing, ' he shouted, and ran up to his bedroom. Perhaps he was responding to the uncompromising note of Bunyan's plain-speaking Englishman. But once the rules were agreed then they must be followed to the bitter end, without bending or cheating. His Nanny found the same when playing with him.

The thing that stands out most in my mind was his integrity and his intelligence for a child so young as he then was, also you couldn't camouflage anything from him. I remember one day Alan and I playing together. I played so that he should win, but he spotted it. There was commotion for a few minutes. …

In February 1919, Mr Turing returned after three years' separation. It was not easy for him to re-establish his authority with Alan, who had a good line in answering back. He told Alan once to untwist his boot-tongues. 'They should be flat as a pancake, ' he said. 'Pancakes are generally rolled up, ' piped back Alan. If Alan had an opinion, he said that he knew, or that he always knew; he always knew that the forbidden fruit of the Garden of Eden was not an apple but a plum. In the summer, Mr Turing took them for a holiday at Ullapool, in the far north-west of Scotland, this time a distinctly posh holiday, complete with gillie. While Mr Turing and John lured the trout, and Mrs Turing sketched the loch, Alan gambolled in the heather. He had the bright idea of gathering the wild bees' honey for their picnic tea. As the bees buzzed past, he observed their flight-paths and by plotting the intersection point located the nest. The Turings were vividly impressed by this direction-finding, more than by the murky honey he retrieved.

But that December his parents steamed away and Alan was left again with the Wards, while John returned to Hazelhurst. Their father was transferred at last to the metropolis of Madras to serve in the Revenue Department, but Alan stagnated in the deathly ennui of St Leonards-on-Sea, concocting recipes. His development was so held back that he had not even learnt how to do long division by the time of his mothers return in 1921, when he was nearly nine.

His mother perceived him as changed from 'extremely vivacious – even mercurial – making friends with everyone' to being 'unsociable and dreamy'. There was a wistful, withdrawn expression in photographs of his ten-year-old face. She took him away from St Leonards and, after a summer holiday in Brittany, somewhat spoilt by the constant counting of francs, she taught him herself in London, where he alarmed her by looking for iron filings in the gutter with a magnet. Mr Turing, who in May 1921 had again been promoted to be Secretary to the Madras Government Development Department, responsible for agriculture and commerce throughout the Presidency, returned once more in December and they all went to St Moritz, where Alan learnt to ski.

Miss Taylor, the headmistress of St Michael's, had said that Alan 'had genius', but this diagnosis was not allowed to modify the programme. In the new year of 1922, Alan was launched on the next stage of the process and was sent off to Hazelhurst like his brother.