At some time in your life, you’re sure to have played the telephone game: where each player whispers a message into the next person’s ear, and the fun lies in seeing how it changes as it passes down the line. The brilliantly-simple concept driving Telephone is to put that same process put on stage. In an extended series of two-handed vignettes, we watch a rumour change and twist as it’s passed from person to person.

At its heart, Telegraph is a sketch show: we meet boldly-drawn characters and incongruous situations, with the humour often found in the gap between the public persona featured in one scene and the private individual we see in the next. Each character appears exactly twice – once as they hear the rumour, and once as they pass it on – a genius approach which provides constant novelty, but balances the episodic structure and helps the narrative flow.

Though the personalities are often stereotypes, they’re never lazy ones, and – in the few minutes we have with each – Ferdinand Ray’s script packs in enough back-story to make us care. The troubled hairdresser’s second appearance is a particular highlight, finding space for genuine poignancy alongside some camply arch humour. A handful of the scenes might have lasted a few beats too long, but the six-strong cast sell all the roles with flair and the jokes landed well with everyone in the room.

When it comes to the rumour that drives the plot, however, the balance feels slightly off. In the first few exchanges, the story changes in small, understandable ways, credibly reflecting the assumptions or prejudices of the gossipers. In the middle, it seems to be heading in a dark direction, towards a fake-news conspiracy theory with echoes of Pizzagate. But then it takes a total swerve in a couple of extraordinary jumps – alongside an important-seeming plot point which, I’m afraid to say, I simply didn’t understand.

The pay-off when the message reaches the end of the line would be funny if the rumour had been ridiculous all along, but it looks flimsy atop the solidly-built foundations of the earlier scenes. Telephone would work brilliantly as a jet-black satire or as a heightened comic caper, yet it doesn’t quite commit to either.

It’s a fun hour, though, with a profusion of entertaining character studies and some magnificently unexpected scenarios. The complex logistics of the frequent scene changes are handled seamlessly too – and that’s no faint praise in the chaos and constraints of a busy Fringe venue. I’d love to see more done with the inspired central conceit, so I’ll keep my fingers crossed for a Telephone 2 next year.