Reaching the high chain-link fencing topped with barbed wire, he came to a halt and once more drew Rita’s scarf from his pocket.

Harvey sniffed deeply, searched amongst the gorse and long grass by the fence and then worked his way along the perimeter until he reached the country lane in the valley. The fog was thinner here, the visibility just good enough to make out the fields of wheat, and the ghostly white fleeces of grazing sheep.

Ron followed him, watching his every move. If his instinct had been right, Harvey should pick up her scent very soon.

Harvey stood in the lane, sniffing the air, his ears pricked – and then he shot off towards the airfield.

Ron hurried after him, straining to hear his bark which would signal that he’d found her.

It came within minutes, muffled by the fog and very distant.

Ron strode towards the sound, his boots crunching on the loose gravel of the country lane as he passed the silent fields and approached the far reaches of RAF Cliffe’s runways and security fencing. There were no planes tonight, and the fog was now rolling over the hills into the valley, deadening all sound but for the frantic high-pitched and urgent barks of his dog.

Harvey galloped out of the fog, saw Ron, gave a single bark and turned swiftly back at the faint cry for help.

Ron frowned as he broke into a trot. That wasn’t Rita’s voice.

He found them at the side of the road, half-hidden in the undergrowth of a high hedge, the mangled motorbike on its side in a nearby ditch, Harvey going back and forth between them, whining with concern.

Ron patted his head and praised him quickly before fighting his way through the brambles to the two girls who were huddled together for warmth and comfort.

‘I don’t know how you found us, but thank God you’re here,’ said Sarah tearfully through chattering teeth. ‘We’ve seen no traffic for hours and although we’ve been calling and calling, no one’s heard us.’

Ron hid his surprise at seeing her. ‘Where are you hurt?’ he asked, switching on his torch and taking in their deathly white pallor, their scratched faces and the awkward angle of their limbs.

Rita’s brown eyes were huge in her ashen face as she tried to move her leg and gave a sharp gasp. ‘It’s my knee and Sarah’s ankle and arm.’

He untied the bundle and swiftly wrapped them in the blankets, for although Rita was wearing her fleece-lined leather flying jacket and thick trousers, Sarah had only a lightweight overcoat over a cotton dress, and both girls were trembling with shock and the cold. ‘How did this happen?’ he asked, glancing at the damaged motorbike.