In February 1950, Pontecorvo's Harwell colleague Klaus Fuchs was arrested for espionage, and the AERE began to take security more seriously, and Pontecorvo was interviewed by Henry Arnold, the security officer at AERE. While Arnold had no evidence that Pontecorvo was a Soviet spy, he did feel that he was a security risk, and recommended that he be moved to a position where he did not have access to Top Secret material. Herbert Skinner suggested to Pontecorvo that he apply for a newly created professorship at the University of Liverpool, where Skinner held the Lyon Jones chair of experimental physics. In June 1950, Pontecorvo was offered the position.