It’s 3am and I’m standing in the pitch black, gripping the hand of a woman I met just hours earlier. A man in his 30s has joined us, so we’re told, and is peering at us both intently. I peer back, trying to make out his supposedly haggard features in the darkness. Nothing. He’s not pleased that we’re here, apparently – and at that moment, I’m not sure I am either. I hold my breath, wait for something terrible to happen – but then he’s gone. Time to try again.

“Spirits of Bodmin Jail, make yourselves known!” commands Kirsten Honey, our clairvoyant guide.

We’re halfway through Bodmin Jail’s After Dark experience, but this call to the deceased still brings a tension to the room. The former prison, on the edge of Cornwall’s Bodmin Moor, is said to be one of the UK’s most haunted places. Built in 1779, it once housed prisoners as young as five and saw more than 50 public executions. It’s also home to the UK’s only remaining execution pit, last used in 1909. Wandering round it in the dead of night – the tours run from 8.45pm to 5am – even the sceptical soon feel on edge.

The evening begins with a three-course dinner at long tables under high, vaulted ceilings in the alluringly gothic Governors Hall. (The setting is more impressive than the food, which is a tasty but rather dated prawn cocktail and sticky toffee pudding-type affair.)

Then it’s coats and jumpers on for a night-time walk around the prison and grounds, with workshops led by experts in the paranormal. In the naval wing, Mark Rablin, medium, Reiki master and lead tour guide, tells us about his first encounter with the supernatural: a shadow he believed to be his own, until it sprinted away from him. Between them, Rablin and Honey have enough ghost stories to keep visitors entertained, even in the absence of actual apparitions.

Mannequins dressed as prisoners past become unnervingly lifelike as we listen to tales of their ghostly activities. Unmarried mother Selina Wadge, executed for the murder of her child in 1878, continues to haunt the prison apparently, choosing children and pregnant women in particular.

With the lights out, spirits are summoned once again. I feel cold, but can’t tell if it’s because it’s the middle of the night in a draughty room or, well, something else. But Rablin is keen to dismiss anything that might be misinterpreted as paranormal. Something brushing your head in the tower? Probably a bat. Those glowing orbs floating past the CCTV screens? Just dust. And by all means take photos – but don’t be fooled by any reflections in the retro-fitted glass windows.

In between ghost hunts there are exercises in “energy manipulation” (learning to recognise our own, and to feel that of others) and a bit of “table work”: lightly resting a finger on an upturned wineglass on a wooden table. Our glass moves slightly and fairly slowly – but does nothing more impressive. Perhaps it’s a quiet night – people have experienced everything from hands being tugged to the sensation of being strangled – but it’s scary fun nonetheless.

Each spirit-seeking foray is followed by a welcome return to a warm and well-lit room (a kind of ghost-free safe space) with hot drinks enough to last all night. At the start, the 5am finish felt daunting, but it’s an adrenaline-filled event, and the hours pass quickly.

Back at my hotel about half an hour later, the lights in my room flicker uncontrollably. Did they do that before? I turn them off and, just as I drift into exhausted sleep, the radio switches itself on – to static. I lie in bed, heart racing. I may not have seen any floating torsos at Bodmin, and I’m fairly confident no spirits “passed through me” – but I have been well and truly spooked.

• After Dark events at Bodmin Jail run two or three times a week, £90pp including dinner, over-18s only