Viktor Koslov

Played by Andrew Scott

Viktor is a KGB agent who has been sent to Britain to work at the Russian Embassy, though truthfully, he’s involved in a plot far greater than even he first realises. An old University friendship with Charles Thoroughgood is rekindled thanks to pressure from higher powers on both sides. When they meet, Viktor reveals a shocking revelation about Charles' family that shatters his illusions about the true nature of betrayal.