We share our house, and I don't just mean with our dog and six cats. Nor do I mean the recent infestation of bees (harmless enough) and the occasional mouse (just what do those cats do exactly?).

All kinds of animals turn up from time to time. We've had huge toads in the basement, owls in the stove flue — we've rescued two so far — and a flock of starlings. Various kinds of beetles wander through. However, today brought a new experience.

I was in one of the rooms in our converted attic. I have a desk pushed against the side wall that was constructed just under one of the main roof beams. Behind the wall, then, is a small and unreachable attic space. Working at my computer my attention was caught by a movement just at the edge of the desk, in the shadow of the beam. Whatever made it had disappeared, but after a moment's reflection I concluded that I'd seen the tip of a cat's tail.

I looked under the desk. No cat. But while I searched something else appeared — something long, thin and with a flickering forked tongue.

Sitting bolt upright once more, I examined the rat's nest of cables behind the computer monitor. And sure enough, wound into the cables and around the nice warm UPS was a young grass snake.

We get plenty of them in the garden. One even left its old skin hanging outside our bedroom window one year. And we found a particularly large specimen busily feasting on a massive toad out in the orchard. But this was the first to venture into the house.

It is, of course, unseasonably cold and wet. The snake can be forgiven for seeking out somewhere a little more comfortable. But he seemed a little less willing than me to share this space. As I watched, he slid stealthily through the tiny gap between wall and beam that he'd used to break in. Within a few seconds he'd gone. I'm rather hoping he'll be back. It's nice to have guests.