She was still wearing the football helmet when we set off for Fair Oaks airfield. Her visits to Shepperton, though less frequent, always calmed Sally. She landed like an eccentric Victorian balloonist, tethered to the ground by the children’s affection for her. But once we left its gentle gravity she began to soar away. Blond hair streaming through the open roof, she lay with her arms out of the window, waving to the extras leaving the film studios. The glowing end of her loosely packed cigarette blew a train of sparks into the rear seat and set fire to the ear of a faithful koala. As Henry choked, Sally lunged over the seat and slapped at the smoking embers. She shouted to the young policeman guiding traffic into Fair Oaks, who gazed in awe at her mini-skirt riding over her ice-pale buttocks.

When we reached the car park she noticed a television crew filming the air display. Sally pulled off the helmet and assumed the hard-eyed stare of her favourite amphetamine shades, gazing in a ravaged way at the parked planes and the handsome pilots. The anti-Vietnam protest marches and scuffles with police, the drug busts and cooling-off trips to New York, had given her a terminal Manhattan tremor, part permanent jet lag, part overdose of heroin and time. Like so many others at the end of the sixties, that ten-year pharmaceutical trial, she thought of the media landscape as a life-support system, force-feeding a diet of violence and sensation into her numbed brain.

But sometimes I felt that it was Sally and a few thousands like her who supported the decade, which ruthlessly tapped their fraying nervous systems for the last pulse of energy and excitement. The carousel was spinning ever faster, driven on by Sally as she rode her exhausted unicorn. I hated the needle arms, but loved to see her sweep into Shepperton with presents for the children and endless King’s Road talk. She was happy to camp for hours with Alice and Lucy in their garden tent, baking and icing a birthday cake for a long-serving teddy. Later, when the children were asleep, she lay back on the sofa with her heels in the small of my back, almost strangling me as she seized some slipping memory of her father that I had helped to return to her.