BAFTA-winner Lenny Rush (Am I Being Unreasonable?) has joined the cast of Slow Horses for season 6, which will premiere September 16 on Apple TV. Deadline reported that the new season "kicks off with the Slow Horses on the run as Diana Taverner (Kristin Scott Thomas) embroils them all in a fatally high-stakes game of retaliation and revenge." The season is based on the sixth and seventh books, Joe Country and Slough House, in Mick Herron's Slough House novel series.
The season 6 cast also includes Gary Oldman, Jack Lowden, Saskia Reeves, Christopher Chung, Aimee-Ffion Edwards, Rosalind Eleazar, Joanna Scanlan, BAFTA Award nominee Samuel West, Ruth Bradley, Tom Brooke, Jonathan Pryce, and Hugo Weaving. A seventh season is already in the works and will be adapted from the eighth book, Bad Actors.