Is there any sound more upsetting than the cry of a small baby? I’m not referring to the full-scale shrieking of an angry or tired or hungry infant, rather the pathetic mewling of a baby that is alone and neglected. 

Last Autumn, I decided I would leave the family at home in Droitwich and give myself a much-needed break, doing a little walking, photography and bird-watching. Not wishing to strain the family finances, or provoke marital dissent, I rented a caravan at Port Eynon on the Gower peninsula, not far from the beautiful beach at Rhossili. 

Arriving late on the Friday after a hard week at the college and the horrors of the M4 around Cardiff, I contented myself with pasta and pesto and a couple of cans of Tiny Rebel Cwtch. The facilities on the site were no more than adequate, but at that time of year it was at least quiet, with no ball-games or radios to disturb the peace. 

I slept well despite the lumpy bed and on Saturday I pulled on my boots and picked up my binoculars ready to sally forth. A thin drizzle met me, but I felt sure it would pass, and it did. I began my walk, along the Wales Coastal Path at the edge of the deserted beach. It was sad to see the paucity of sand in some places, a casualty, according to an old man whose path I crossed, of dredging in the Bristol Channel. 

The birds were unremarkable, mostly waterfowl and the odd Wader, but I did spot a Tern and a Skua and was able to take a few shots with the Nikon. Nothing award-winning, but good enough to show around. 

By the end of the day, I was a little tired. Bored with my own cuisine and company, I decided to stop for a pie and a pint at the The Ship Inn. Surprisingly, it was busy, but then it is the only pub in the village and this was a Saturday night. 

A second and third pint followed and I enjoyed some good-natured joshing from the locals and staff. A couple of friendly dogs lay on the floor. I don’t like dogs, but this was their home, not mine.

And then I walked back in the dark, swaying slightly, to the caravan where I made myself a coffee and settled down with Lee Child. 

I had barely begun to follow Reacher on his latest knuckle-crunching adventure when I heard it. That sound. The thin, chilling whimper of a baby in distress. I ignored it as best I could. Whoever’s problem it was, it was not mine. 

It went on. After a time – 10 minutes or an hour – I could stand it no more. Picking up my torch, I crossed to the caravan the sound was emerging from. There were no lights, but that was no surprise because by now it was after midnight. 

With some trepidation, I knocked gently on the aluminium door. No answer. I knocked again, more firmly. The third time was loud enough to wake the soundest sleeper, unless drugged or drunk. 

The campsite had no overnight manager, but there was a telephone number on a square of paper stuck to the office window with brown sellotape. I woke the man up, for which he didn’t thank me, but he agreed to come out. 

He was a short, stocky figure in a black nylon anorak and dirty jeans. ‘Where is it?’ he asked. We walked to the caravan together. He banged on the door, as I had done, then turned to me. ‘I got a master key. Shine your torch over yer.’ 

He took a huge circular ring from his jacket pocket and sorted through the keys until he found the one he wanted. Then he tried it in the lock.

The cylinder turned, but the bolt stayed firm. He tried again and again. “What did you say you ’eard?” he said. 

‘A baby,’ I said. ‘A tiny baby.’ 

‘I’ll call the police,’ he said, taking an old Nokia from his pocket. ‘They’ll be yer in 20 minutes, they says.’ 

He offered me a cigarette. I thanked him but refused. 

‘Bird watching, eh? See any?’ 

I told him I had. 

‘My bird-watching days is over,’ he said, ‘If you gets my drift.’ 

The 20 minutes passed slowly but then a white and red BMW with Heddlu on the side trundled down the hill. The officers, a man and a woman, came to the caravan and banged on the door. ‘Did you try the lock, Dai?’

‘What do you take me for?’ 

‘Sorry. I had to ask.’ 

The officers walked around the van, shining their torches in and occasionally pushing against it and rocking it. 

‘All right,’ said the copper. ‘We’ll go in.’ 

From the boot of the BMW he produced a heavy metal cylinder with handles on either side. ‘Stand back, Cheryl,’ he said, then swung it against the door. On the second attempt the metal splintered. He reached inside and tried to release the lock, but it didn’t give, so he continued bashing the door until it was destroyed. Then they stepped inside.

I hung back, but Dai followed. 

The three emerged, Dai first. 

‘Nothing,’ said the male officer. ‘No-one in there. No-one been there for a while.’

‘Sorry,’ said Dai. ‘I ’ad to call you. No choice, see.’

They gave me a look. ‘Yes,’ I said. ‘I’m sorry. You can’t be too careful, can you?’

‘Have you been drinking, sir?’ said Cheryl. 

‘No. Well, hardly at all.’ 

‘I should be getting back, if I was you. Get some sleep.’ 

I did as I was told. I closed my door, took off my boots, cleaned my teeth, pulled on my pyjamas and climbed between the sheets, shivering. 

Then it started again.