Continuity mistake: Opening scene is a 1947 flashback with Claire Foy giving her 21st birthday speech. When the camera is near, the black microphone is near her face with no sign, but in a long distant shot, there is a black BBC sign on top of it. (00:04:11)
Factual error: Michael Shea was not forced to resign ignominiously as Press Secretary in 1986. He actually left in 1987 and was appointed Companion of the Royal Victorian Order for his service.