Where would you choose to spend your last hour on Earth? Probably not stuck on a Tube train. But that’s the fate that awaits six mismatched characters in The End Of The Line, a comic drama about an impending nuclear apocalypse that melds character-driven humour with existential themes. There’s an over-sharing tarot reader, a jilted lover, the MP for Chpping Barnet… and less than 60 minutes on the doomsday clock.

The action hits its peak in a couple of defining set-pieces – one describing a nightmare school trip, another that’s so magnificently surprising I daren’t reveal even the theme. Both are visual, dynamic, and wilfully silly, pressing the strangers on the train into unexpected roles in a flurry of choreographed humour. Though the rest of the show doesn’t quite match the spot-on timing of those scenes, the laugh count stays high, while the dialogue reveals more about the passengers and draws meaning from their disparate stories.

There are quieter moments, too. The stand-out performance for me comes from Liam Howie as Darren, who’s the driver of the doomed train and as such, speaks for the common man. His simple regrets – he’ll never see his wife or his grandchildren again – contrast eloquently with the passengers’ main-character energy; more than once it falls to Howie to softly pull the spiralling narrative back down. And there are serious themes here, for all the travellers, around what’s really important in life and how you’ll be remembered by those you leave behind.

But the plot has holes you could drive a Tube train through. I can’t explain it properly without major spoilers, but the first ten minutes of the script seem to occupy a different universe to the conclusion – and, though we know by the end how the travellers got stranded, that doesn’t explain why nobody is coming to save them. A comedy play can survive a rickety storyline, but the more I thought about it afterwards the less sense it made, and the underlying lack of logic is just too great to ignore.

Similarly, though the set is magnificent and packed with subtle humour, it weirdly undercuts the stuck-in-a-tunnel narrative by showing a station through the window. Taken as a whole, the production doesn’t quite add up. The final speech is moving, though, and the ending gives us closure of a kind – as the characters break out of the pigeonholes we may have put them in, and learn the importance of true connection. We’ll hopefully never face the apocalypse, but we all need to mind the gap.