‘Where did you get these?’ I asked.

‘Sports warehouse,’ said Al. ‘They’re children’s floats for swimming pools.’

He’d picked them up on his way back from Birmingham where he’d bought the phones. Reputable shops won’t sell you more than three disposables at a go, but fortunately everyone else will – especially for cash. One of the advantages of being the police is that when you want to buy something slightly dodgy, you generally know where to shop.

There were thirty of the buggers, and they filled up the back of the Asbo. I also kept four phones still in their plastic packaging for use later.

‘Did you see it?’ asked Al, as he helped me carry the magic detectors to the car.

‘See what?’

‘There was a sighting two nights ago up near Croft Ambrey,’ said Al.

We went back into the shop and opened up my laptop and loaded up the tracking software.

‘Multiple witnesses, classic Type V, light source, no visible body,’ said Al as we waited for the diagnostic test to run. He was surprised that it hadn’t made the national papers. ‘But your lot did find those kids that day,’ he said, and implied that he thought the two were related – which of course they were.

The laptop ran through each of the detectors in turn before putting them into passive mode. Being cheap disposables they didn’t have GPS, so I’d have to log each location as I planted them.

‘Aymestrey’s always been a hotspot for close encounters,’ said Al. ‘Some of them very difficult to explain away.’

I asked him if he had a list, and he directed me to a website called UKUFOindex.com where all UFO sightings were indexed and cross-referenced for any member of the UFO community to access. I made a point of noting down the address in my notebook.

We ran one last test to ensure that the detectors were registering on my laptop.

‘Any abductions?’ I asked.

‘Loads,’ he said. ‘But none verified.’

Al, while being a firm believer that extra-terrestrial life had visited Herefordshire, was a firm agnostic on the whole abduction and cattle mutilation thing. Although he lived in hope.

‘Just think what would happen if we had irrefutable proof that we weren’t alone,’ he said. ‘Think what a difference that would make.’

It was about then that I got the idea for the investigation technique that I call, for reasons too geeky to mention, the reverse Nigel Kneale. I paid Al in cash, got his personal mobile number in case I needed a technical consult in the middle of the night, and headed for Leominster nick.