According to some of his colleagues on "Doctor Who", he could be a difficult person to work with. Others, though, such as actors Peter Purves and William Russell, and producer Verity Lambert, spoke glowingly of him after more than 40 years. Carole Ann Ford, who played the Doctor's granddaughter Susan, has said she and Hartnell "got on terribly well", saying "It upsets me when I hear people saying he was difficult to work with, he was very sweet" Hartnell also adored Verity Lambert, and had great respect for Waris Hussein. Hartnell also admired singer Paul Robeson. In his "Desert Island Discs" interview, Hartnell stated that Paul Robeson was his hero and described him as having a voice like crushed velvet.