‘Allons y,’ I said, and led off down the left-hand track.

We’d gone on another couple of hundred metres, around a turn and past a turn-off that Dominic identified as heading down to Croft Castle, when we heard the hoof beats.

Beverley heard them first, but as soon as she’d pointed them out I heard them as well. Hooves hitting the ground in a fast jaunty rhythm. A slow trot, I learnt later – sometimes known as a jog.

It took a couple of rounds of shushing and craning to establish that it was coming from behind us. I put down the cricket bat to anchor the werelight in place and ‘jogged’ back five metres to see if I could re-establish my night vision. With the light behind me the track became a milky strip, snaking between the vertical shadows of the trees, whose pointed tops marched off like fence spikes. The moon hung full and round and almost perfectly aligned with the track.

If this wasn’t your actual moon path, I thought, it would certainly do for the postcard.

I couldn’t see a horse, but I could hear the hoof beats getting closer – and picking up the pace.

‘Let’s get off the road,’ I said.

Neither Beverley nor Dominic argued, even when we found ourselves pushing through the chest-high bracken that had lain invisible in the darkness until we blundered straight into it. If anything, we were grateful for the additional cover as we crouched down and waited for the hoof beats to get closer.

I glanced up at the werelight obediently hanging directly over the track where I’d left it. The colour was definitely beginning to edge into the red as whatever approached sucked up the magic and lowered the frequency of the emitted light.

The hoof beats slowed to a walk and then a cautious amble. They sounded large, the hoof beats, great big dinner-plate-sized hooves that thumped down onto the dust of the track with authority.

I watched through the gaps in the bracken as the werelight dimmed down to a sullen red and Princess Luna made her appearance. It was transparent but refractive, a statue of living glass, the dying light from the werelight tingeing its shoulders and haunches with red and outlining the long spiralled horn that rose from between its eyes.

Then the werelight popped out and suddenly it was there, huge and real and sweaty and pale in the moonlight, its horn bobbing left and right as it swung its head and sniffed the air.

I resisted the urge to push further back into the bracken.

Then the head snapped back to point down the track, the big muscles in its haunches bunched, flexed and the beast sprang forward, its vast hooves kicking up dust and splinters of rock.

We scrambled out of our hiding place and stumbled out to stare after the unicorn as it vanished around a curve in the track.