Have you ever wondered what your dog dreams about when sleeping? The twitching, the quiet yelps, the sudden burst of movement: these all suggest a world unfolding just out of reach.

When Wolsey leapt up one evening and began chasing something I couldn’t see, I dismissed it as nothing more than a vivid dream. But weeks later, a small discovery in the brickwork of my home made me question whether it had been so ordinary after all.