Sasha Gavrik is the son of Elena Gavrik and Ilya Gavrik and a FSB officer. He first comes to London as a member of his parent's protection unit. He first appears when he threatens Harry Pierce in Harry's home because he believes Harry is still running his mother and he is worried about her being in danger.Harry, who is not running Elena, realises that somebody is posing as him to get secret information from the cold war period which puts the relationship between Russia and England at risk. At the end of the episode Harry reveals to Ruth Evershed that he and Elena were once lovers and that Sasha is, in fact, his son.