The Crown season 4 sees the breakdown of Prince Charles and Diana's marriage and a threat that hints at a major conspiracy theory around Diana's death.
The final episode of Netflix's The Crown season 4 shockingly features a major reference to one of the most compelling conspiracy histories related to the tragic death of Princess Diana. Not only does the very final shot of the finale outright reference her final moments before the crash that killed her (albeit in a subtle way), but a loaded interaction with Prince Philip set up the possibility of The Crown season 5 offering a theory on the real cause of Diana's death.
Season 4 hurtles more quickly through the major events of the 1980s, with The Crown this time specifically set between 1979 and 1990, taking in the assassination of Lord Mountbatten by the IRA, Charles and Diana's whirlwind engagement and marriage, Margaret Thatcher's entire tenure as Prime Minister of Britain and other events specifically tied to the clash of the monarchy's traditionalism and the advances of modernity. The richest thread - and arguably the season's most important given what follows - is the tumultuous relationship between the Prince of Wales and Diana Spencer, which begins when the latter is still a teenager and closes out the season as Charles seeks the right to divorce his wife.
The final episode of The Crown season 4 sees both Charles and Diana seek their own ways out of their broken marriage, not least through mutual adultery but also by more official methods. Charles is refused the right to serve divorce papers by the Queen while Diana's defiant attempt at a rebellion against the Crown's perceived suppression of her in a loveless, rudderless marriage ends shockingly in a threat from Prince Philip. He tells the Princess to toe the line, to give up on her individualism, and accept that the only thing that matters - the only person in the entire family who is not an outsider - is the Queen herself (Olivia Colman). Given the way history played out, with Diana's estrangement from the Royals in the wake of her divorce from Charles and the myriad conspiracy theories around her death, Philip's threat rings loudly and chillingly.
Diana's death inspired a number of conspiracies, speaking mostly to the existence of a motivated, unknown party who worked with either a photographer, MI6 operatives, or the SAS to kill Diana. Somewhat infamously, a documentary was made in 2011 by Keith Allen and funded by Mohamed Al-Fayed - the father of Diana's fellow tragic passenger Dodi - called Unlawful Killing. It aired as part of the expanded program at Cannes film festival that year but never made it to release because of inevitable legal issues, including leveling claims against the royal family as "gangsters in tiaras" and suggesting Prince Philip orchestrated the murder. Al-Fayed himself has suggested the same thing repeatedly and Diana's biographer Martyn Gregory accused the film of parroting ludicrous theories.
It isn't only Philip's open threat to Diana on The Crown, which shocks her enough to seemingly choose, temporarily at least, to accept her misery that plays into some of the conspiracies. The final shot of Diana shows her captured ominously in the flash of a camera as the Royal Family gather for a Christmas photograph, harking not only to the involvement of the paparazzi in her death but also another conspiracy theory. Former MI6 agent Richard Tomlinson claimed that a bright white flash blinded driver Henri Paul, though his evidence was rejected (despite several eyewitnesses corroborations). The point of the moment is not necessarily to give weight to those theories - especially as the paparazzi's pursuit of Diana and Dodi's car was ruled as a cause of their death by the British inquest - but to reflect the wider response to the crash. The conspiracy theories are an important part of the culture around the Royal Family heading into the period that The Crown season 5 will portray and there was such wide belief in Britain (particularly in the white flash theory), that leaning into them even subtly makes sense. Whether the show will offer a stance on what truly happened or not, however, remains to be seen.