Factual error: Sir Martin Charteris, depicted as being Private Secretary throughout the series (which begins in 1979), actually retired in 1977. Sir Philip Moore and Sir William Heseltine were the real Private Secretaries during this period.
Factual error: In the final scene Lady Diana is being pursued by photographers during the time of her courtship with Prince Charles. The most prominent car in the scene has an 'X' registration plate. The registration letter 'X' was only used from August 1981 onwards - after the wedding of Charles and Diana.
Factual error: The Guards band playing at the garden party (in 1982) includes female musicians in the same uniform as the men. Until integration in 1992, the only female musicians in the British Army were members of the Band of the Women's Royal Army Corps. Women did not join Guards bands and wear their uniform until well into the 1990s.
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.
Factual error: Diana's actual coif in her late 20s was much fuller at the top and the sides, and slightly longer in the back than this depiction.