Is Slow Horses the best spy TV show ever made? It feels like the stories John le Carré would tell you at the end of a depressing family party, holding onto the table for comfort as he slurred “OK, let me tell you what it was really like”. Le Carré’s double-crossing spooks at least believed in something even if it was only money. The Slow Horses are too cynical even for that. In the new season, as with the old, Gary Oldman’s flatulent, whisky-soaked misanthrope Jackson Lamb steals every scene so comprehensively that he makes off with the ones he isn’t even in. Lamb spies in the way a shark swims – superbly, beautifully, but with dead eyes and because if he ever stops he’ll die. As ever, the dark past – this time something unspeakable from Istanbul – resurfaces, requiring the Failures of Five, the spooks who messed up and are condemned to eke out their careers in the rundown Slough House, to stumble into the light and slowly, meticulously, almost carelessly destroy and humiliate everyone including themselves. Unmissable.