Psi

Psi was a hacker / bank robber with an augmented brain who helped the Doctor and Clara rob the Bank of Karabraxosepisode in the episode ' Time Heist '.

Hardly anything was known about Psi. He had previously erased his memories prior to the episode after being convicted as a criminal, and mentioned in doing so, he had erased all his memories of family and friends too. When questioned, he simply replied: "I suppose I loved them."
 * He has a prison code on the back of his neck.
 * He is played by Jonathan Bailey (Leonardo, Five Children and It).