Slow Horses fans have been left in shock after the devastating finale of season six that saw several characters gunned down.

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Season six saw the return of Olivia Cooke’s MI5 agent Sidonie Baker after a four-year absence from the hit thriller. The happy reunion with fellow spy River Cartwright (Jack Lowden) didn’t last long though, with the pair fleeing from Russian sleeper agents.

The final episode aired last night (Wednesday October 21) and saw MI5 employees Louisa, Standish, Moira and Shirley joining up with Roddy, Emma Flyte, Reese Nesmith and River in a safe house, before they’re attacked by River’s father Harkness and a couple of henchmen.

Meanwhile Slow Horses’ boss Jackson Lamb (Gary Oldman) confronts Diana Taverner (Kristin Scott Thomas) about the Russian conspiracy that’s put his friends and colleagues in the crosshairs.

I’ve just finished watching Slow Horses Season 6 Episode 6. I always trust Apple TV to deliver, but this?…