When it comes to Agatha Christie adaptations, there are normally two possible responses to the denouement. One is a deep satisfaction that the unlikeliest suspects were the inevitable culprits after all. The other’s the same as that – except approximately a quarter of an hour later you suddenly find yourself thinking: ‘Hold on a minute…’

But with Agatha Christie’s Seven Dials, neither was the case. The unlikeliest suspects remained laughably unlikely even as their guilt was revealed – and the ‘Hold on a minute’s came not after the show finished, but with pretty much every twist of a plot that, almost impressively, kept finding new levels of preposterousness to scale.

The setting was the mid-1920s – which naturally meant that in a country house, assorted bright young things were dancing the Charleston and exchanging such dialogue as ‘Hello, Bundle’ ‘Hello, Socks’ as their elders looked on with pursed-lipped disapproval.

The following morning, one of the BYTs was found dead, an empty bottle of sleeping draught beside his bed. So had he committed suicide? The answer was, of course, no – although the only person who thought he hadn’t was his soon-to-be betrothed, Lady Eileen ‘Bundle’ Brent (Mia........

© The Spectator