Speaking exclusively to Express.co.uk, royal expert Richard Fitzwilliams said: “Prince Harry and Meghan Markle’s contract with Netflix has been renewed in a downgraded form, which will give Netflix first option on what they produce.

“Netflix’s Chief of Content, Bella Bajaria, has recently praised the enormous success of their highly controversial six-part docuseries Harry and Meghan. They want something royal from the couple whose royal links are their only claim to fame.

“This (a Diana documentary) could be it. We know from his memoir Spare how deep his affection for his mother was and how devastated he was at her passing. This is obviously totally understandable.

“Diana was like a meteor. She was the world’s most glamorous woman, whose charitable activities have rightly become legendary, but who was also manipulative and had a fatefully symbiotic relationship with the media. The War of the Waleses, between her and Prince Charles, which ended in divorce, was ferocious at the time.”

Fitzwilliams continued: “If the proposed documentary featured anything controversial, it would gravely endanger the reconciliation Harry has said he wants with his family although it would undoubtedly draw the audience Netflix wants.

“This programme, especially now that Camilla, the woman she (Diana) regarded as her rival, is now Queen Consort, also, potentially, has enormous dangers for Harry’s future relationships with his family.

“If reconciliation is desirable, but seems unlikely, peace is essential. This (the documentary), if it happens, could restart conflict.”

Prince Harry and Meghan Markle have not confirmed whether such a documentary is in the works.