The W.E. star played a young Thatcher in acclaimed U.K. TV drama The Long Walk To Finchley in 2008, which was based on the Conservative politician's early career.
After researching Thatcher for the role, and studying some of the deeply unpopular decisions she made during her time in office, the actress is adamant the ex-leader felt little empathy with the British people.
She tells Britain's 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. As I understand it, the term implies a tendency not to feel as much guilt about one's actions as perhaps one ought to.""
Thatcher, the U.K.'s first female Prime Minister, was in office for 11 years and came under fire from the public for her clashes with trade unions, which led to crippling strikes, and the introduction of a new tax.