The real [31] was a British civil servant who spied for the KGB for 40 years [28]. Unlike the fictional Joan, who was a physicist, Norwood was a secretary at a metals research association [31]. She was finally exposed in 1999 at the age of 87 but was never prosecuted due to her age [28].
"Red Joan is unlikely to appeal to younger audiences... but it will win fans because there is much to admire: The solid acting... [and] evocative cinematography." [18]
"The characters are vividly realized, and their manipulation of the innocent Joan into traitorous actions is built up carefully and made very believable." [24]