Andrea Riseborough says she believes Lady Thatcher, who she played in a BBC drama, had "psychopathic tendencies".
Andrea, 31, played the young Margaret Thatcher in The Long Walk To Finchley, based on the former prime minister's early years in politics.
The Never Let Me Go and Made In Dagenham actress told the Radio Times: "Mrs Thatcher had oversights when it came to thousands of people. No, millions. She is still untouchable for many because she didn't operate in the way others did.
"Her connection with humanity was a very loose thread. Emotionally, she was not in touch with herself or anybody else. As well as being such an intelligent woman, I would say she had psychopathic tendencies."
She added: "As I understand it, the term implies a tendency not to feel as much guilt about one's actions as perhaps one ought to."
Andrea, who starred in Madonna's WE, is up for an EE Bafta Rising Star award, which recognises new talent in the film industry.
She won critical acclaim for her role in political thriller Shadow Dancer last year and will next appear in crime drama Welcome To The Punch.