‘So they dropped me in a vat of oil when I was born, I suppose?’

‘Don’t be a dolt.’

They stayed in RAF barracks and ate in military messes or, if no beds were available, would take bed and breakfast at local inns, for which they’d been given a modest allowance. After the long months of hard graft, with bosses breathing down their necks expecting results and asking for solutions ‘by yesterday’, the freedom was intoxicating.

Not that they were taking it easy. Their days were busy with visits, taking detailed notes, copying technical drawings and making sketches of their own, the evenings spent writing up their reports and developing potential ways in which the friendliness, or otherwise, of an aircraft could be detected by a radio wave. At night, easing himself into sleep, Vic would recite their names: Blenheim, de Havilland, Handley Page, Avro, Vickers, Fairey, Armstrong. When he finally slept he dreamed of engine sizes, wing lengths and torsion strengths, images of circuit diagrams and the configuration of instrument panels.

One weekend they took a detour to visit Johnnie’s home near Petersfield, on the South Downs. When Vic fretted about not having anything smart to wear, Johnnie just laughed. As soon as they arrived, Vic understood why.

They were greeted by his wife Lizzie, a strong, handsome woman digging up potatoes in a small allotment at the front of a semi-detached Victorian farm cottage. She threw down her spade and ran to Johnnie, smothering him with kisses and smearing his face with earth from her hands, but no one seemed bothered. Two adolescent children emerged and jumped on their father, almost knocking him to the ground and then dragging him indoors, leaving Lizzie and Vic to introduce themselves.

‘Vikram Mackensie.’ He felt awkward, witnessing such effuse expressions of physical affection. ‘I’m sorry to intrude.’

‘Don’t be silly, we love visitors,’ she said, wiping her hands on her apron. ‘And we’ve heard so much about you, Mac, or should I call you Vikram?’

‘Vic will be fine, but I answer to almost anything. “Here, you” works well.’

Inside, he accepted a mug of tea. The children, a girl and a boy, were talking ten to the dozen to their father, showing off their toys, models and workbooks, leaving Vic time to look around. He’d never seen a room quite so chaotic before: ancient furniture, threadbare carpets, a basket of knitting, a cat nursing kittens in a cardboard box in the corner. Faded watercolours and amateur sketches adorned three walls, and the fourth was covered with books stacked higgledy-piggledy on shelves buckling beneath their weight. Such untidiness usually left him ill at ease, his fingers twitching to restore order, but here he felt immediately comfortable. This was a real home, a place where people cared little about how they looked to outsiders, or about material possessions.

Lizzie produced a delicious supper of cauliflower cheese with kale and new potatoes freshly dug from her vegetable plot. They washed it down with a couple of bottles of beer, and afterwards she served apple crumble and custard. ‘Johnnie’s favourite,’ she said, with an affectionate glance across the table. He responded with the gesture of a kiss, earning him cries of ‘Oh, cut out the soppy stuff, Dad, pleeease,’ from the children.