‘These flowers are weird,’ she said, looking at the foxglove.

‘They’re poisonous, you know,’ I said.

‘They also like an acidic soil,’ said Beverley. ‘Which this shouldn’t be – not when it’s built up on limestone like this.’

‘Because calcium carbonate is alkaline?’ I asked.

‘Exactly,’ said Beverley. ‘Judging by the trees on the slope, it’s pretty alkaline until we get to this cleared area.’

‘Can you get local patches of acidity?’

‘You can get local patches of anything,’ said Beverley. ‘Heavy rainfall can leach out the calcium and the potassium, but,’ she gestured at the slope with its white support tubes poking out amongst a sea of purple foxglove, ‘I don’t think so. And this is proper land management we’re looking at here, so I can’t see the National Trust smothering the land in fertiliser. And even if they did, the run off would have gone into the Lugg and I would have noticed it.’

I put talking to the land management team at Croft Castle on my list of things to do.

‘And everything goes well with palm oil,’ said Beverley. ‘Providing you use enough palm oil.’

I secured another detector at the place where the footpath crossed the logging track. Then we walked down the track to where I judged we’d found the two girls and placed a detector there. The bulk of the detectors were laid out at various strategic points around the wood – anywhere that looked like it was, or might have been, a path at some point in the past. I had planned to walk as far as the Roman Road and place at least four detectors at intervals along that, but looking out across the field where we found the dead sheep I realised I was down to just the spares I wanted to keep against contingencies. I’d have to get Stan and Dominic to swing down and place the ones on the road. So we walked back up through the wood to where we’d left the Asbo.

Strangely, it was while crossing the buttercup meadow that I remembered the way foxglove was used to make a tea to drive away babies that were suspected of being changelings – possibly a form of sanctioned infanticide.

Changelings, I thought, and remembered Hannah’s absolute certainty that the returned Nicole was not the girl she grew up with.

Changelings – the babies that fairies left with human parents when they nicked a human child. In these enlightened times we didn’t have to rely on poisoned tea to determine the ancestry of a child. Although it has to be said that while the science was relatively straightforward, it was the legal issues that were going to be complicated.

‘A changeling?’ said Windrow, and I could I tell from his tone of voice that I’d used the wrong term.

‘A substitution of one child for another,’ I said. ‘Could be classified as an abduction.’