Around the back of the property, there was a swimming pool housed in a glass conservatory and an area for playing various outdoor games such as football, basketball and putting. When George had got this part of the garden levelled and turfed, it was his honest intention to play sports with his son, but this had never quite worked out. Mathew’s autism meant that while as a very young boy football occupied his every waking minute, once he reached the age of eight or nine, his obsession became chess, and by the time he was in his late teens, things had changed again to fantasy and science fiction. Since then, Mathew focussed on the comings and goings of TV shows, such as Dr Who and, more recently, Game of Thrones.

The Barrowmans’ next-door neighbour, Essie Blaketon, was walking her four Jack Russells past the Barrowmans’ home, when her attention was caught by the fact that the electronic driveway gate was wide open and, more disturbingly, there was movement coming from the overgrown garden – and she knew it wasn’t foxes because they always made her dogs bark like crazy until they’d walked beyond the Barrowmans’ boundary. This time, her dogs did not bark at all. Essie paused and she gave her eyes a couple of seconds to adjust to the darkness away from the streetlights – then she saw it. A man was in the bushes of the Barrowmans’ garden. Essie got out her mobile and was just about to dial 999, when the figure emerged and started to sprint in her direction. Once he was out in the open, she could immediately see that it was Mathew – his height and frame were distinctive and, when he moved quickly, the top half of his body seemed to get ahead of the bottom half. When he used to play football day and night, he always ran like he’d tripped over something and was about to fall flat on his face. Mathew stopped and turned and changed direction, as though he simply couldn’t decide on where he should be heading. He was crying, clearly distressed and confused. Essie immediately texted Sally.

George and Sally were less than ten miles away at the local golf club, hosting their annual charity auction to raise funds for St Barnabas’s, in Gloucester, the special school that their son had attended until he was 16. George was on stage, talking up the sale of a vintage SylvaC collection, when he happened to glance down at his wife, who was standing by the edge of the stage supervising the order of the lots. Her face was lit well enough by the light of her mobile phone for him to see that she was ashen. Within minutes, George and Sally were driving home.

‘We should never have left him on his own!’ Sally cried.