Demolishing an ancient cairn is definitely high on the list of things people in horror movies should never do. Especially when the one out in the field near sleepy backwater Six Mile Hill supposedly houses Abhartach, reputedly the original inspiration for Dracula – a scary story that Eugene Moffat (Jack Rowan) and friends enjoy winding up tourists with down their local, the Stoker. When his best mate William winds up impaled on the stones on a boozy walk home, and Eugene’s attempted demolition job makes matters worse, the entire construction team must figure out how to put this haemoglobin-hoovering abomination back underground.

It’s surprising that Shaun of the Dead’s casual Brit domestication of the zombie apocalypse hasn’t spawned more imitators. So it’s cheering, after the gore starts to fly in this Northern Irish vampire flick, to hear bluff construction foreman Francie Moffat (Nigel O’Neill) announce there’s some “serious craic” afoot. Chris Baugh’s film doesn’t balance its piss-taking and blood-sucking duties with as much comedy-horror sprezzatura as Edgar Wright does – but sloshes enough briny humour around to make it more than passable craic itself.

In an innovative touch first showcased in the flash-forward opening, Abhartach literally does drain the blood from people’s bodies – not via the classic neck puncture, but his mere presence causes a haemorrhaging torrent of it. It’s genuinely disconcerting: almost too much so, maybe, highlighting how Boys from County Hell’s horror proclivities are imperfectly meshed with its comedic side. In its funny patches, the film is very funny: father and son Francie and Eugene squabble their way through this undead ordeal like a botched work contract, and the former makes a hilariously male, inhibited attempt to comfort William’s dad. But until the finale – where an unexpected source supplies the climactic stake through the heart – it sometimes feels like two separate films running in relay.

• Boys from County Hell is released on 6 August in cinemas.