This story contains spoilers for the Season 3 finale of “Slow Horses” and from the Mick Herron book series
In the Season 3 finale of Apple TV+ spy series “Slow Horses,” longtime MI5 colleagues Catherine Standish (Saskia Reeves) and Jackson Lamb (Gary Oldman) parted ways after he told her a devastating truth about her beloved late boss, Charles Partner.
After Lamb saved her from kidnappers, Catherine tried to get him to admit he is actually fond of her after working together all these years.
Instead, he took pleasure in telling her that Partner, who she believed had died by suicide years before, was a traitor.