It's by now a well-worn and uber de rigueur trope to have a double act that are not especially getting on. Not in a 'what's he like?' Morecambe & Wise style, more a raw contempt bordering on vicious loathing. It's the driving force behind the comic identities of siblings Flo and Joan (played by real sisters Nicola and Rosie Dempsey) as they take to their keyboards (with its sightlines, The Tron is perhaps not the best venue to have acts sitting down).

Initially they seem fairly content with matters, but soon enough the cracks begin to yield as they actively consider how they would end each other's life with varying degrees of mercy. Flo adopts a withering gaze which she turns on the slightly more jovial Joan as they launch into a series of songs. The opening number throws up important questions about dogging and the Kardashians while a folk song concerning a 'lady in the woods' has its chorus amusingly extended upon each visit, and a tune about seeking love with various Europeans heads towards their own take on Brexit.

Perhaps unusually, there's not even a half-duff musical segment in their set and while the hacked-off attitudes are a winner, they're marginally undercut when the Dempseys drift slightly in and out of character. But that's a tiny niggle about a show that puts a (mildly deranged) smile back on the face of musical double acts.

Just the Tonic at The Tron, until 26 Aug, 2.20pm, £5 or Pay What You Want.