I dread to think what would have happened had I not driven past her that afternoon. It was the winter of 2013, and I was on my way home from my local train station in North Devon. Her head was lolling out of the car window, her hair cascading towards the ground. I thought she was dead. I braked and reached for my mobile to call an ambulance. When I looked again, she was sitting up and staring at me. “Are you OK?” I asked. “I’m calling help.” No answer, so I persisted. Eventually she replied, “I’ve stopped to listen to music in peace.” She didn’t want my help, so I drove home, but couldn’t shake the feeling that something was wrong.

A few hours later, after picking up my daughter from school, I detoured to check the car had gone. It was still parked against the hedge, the engine running. I leapt out, yanking open the doors, terrified the woman was trying to gas herself. The car was empty, but leaving the engine on seemed like a cry for help. We shouted across the valley, but there was no response. Then I drove home, swapping my daughter for my husband. After examining the car, he concluded that it wasn’t damaged and the mysterious woman could have driven away if she wanted to. In the car, we found the address of a farm several miles away. We drove there to find it deserted. We live among steep hills and rolling valleys, and it would be dark soon. Fearing for the woman’s safety, we alerted the police. We planned to keep searching, but they told us to go home and wait by the phone.

About two hours later, the missing persons officer called to say they were searching with dogs. We wanted to help, but were told we could contaminate the search. We waited by the gate, hoping for news, and collared a policewoman walking alone in the dark. She told us the missing woman’s name and agreed we could check the outbuildings on our farm.

Gradually, the lights of the police cars disappeared. I was still up at midnight when an officer rang to say cattle had chased the police dogs and they were worried the woman might be trampled. But he had no idea which field or whose cattle.

I woke my husband and we drove to meet the police. Search and rescue asked us to move all the cattle off the land in a five-mile radius; we told them moving cattle in the dark could cause chaos. When they told us that she might be on our land, my  husband offered to take a member of the team on his quad bike to search our fields. We fetched the bike, but no one came.

Eventually, a traffic jam outside our gate allowed us to “kidnap” two officers and persuade them into our kitchen. My husband showed them a map with the obstacles the woman could encounter: electric fences, badger holes, rivers, ponds. Unfortunately, she wasn’t the only person missing that night, and after a six-hour police search there was no proof she was missing. Finally, the officers agreed to search with us. One went with my husband; the other came with me to check the river. Weeks later we learned that, by then, the official search had been called off.

While the officer searched under a bridge, I walked along the bank. About 10 minutes after we set off, I saw what looked like a lumpen pile of fat, white sausages in our pond. I knew immediately it was the woman. I plunged in. She was lying on her back, her hair flowing in the reeds, like Ophelia. She was alive, just, and I screamed at the policeman to help. Together we carried her and laid her on the muddy shore. I covered her with my coat and talked to her as the police officer radioed the helicopter.

As we waved the policemen off at 2am, we asked them to let us know whether she recovered. They told us the next day that she had a serious bleed on the brain, which explained her strange behaviour earlier. She hadn’t been trying to kill herself; she was probably totally unaware of what was happening. The doctors said she was very lucky to be alive: “Another half-hour, and she would have gone.” We were lucky, too; I often run through that 12-hour rollercoaster, euphoric that we found her alive, but frustrated we didn’t find her sooner.

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