Prince Harry looked set to turn his fire on his brother William on Thursday, as Netflix airs the final episodes of the docuseries about the disgruntled royal and his wife Meghan.
One trailer for the last three instalments of "Harry & Meghan", released last week, already escalated the row between the brothers, who are reportedly now no longer on speaking terms.
In an apparent reference to Buckingham Palace, Harry, 38, accused his family of "institutional gaslighting" and claimed they were "happy to lie to protect my brother but were never willing to tell the truth to protect us".
Another trailer, released on Wednesday saw Meghan's lawyer, Jenny Afia, alleging a briefing war against the couple by the palace "to suit other people's agendas".
Meghan's friend Lucy Fraser added: "Meg became this scapegoat for the palace.
"And so they would feed stories on her whether they were true or not to avoid other less favourable stories being printed."
Afia said the "barrage of negative articles" about the breakdown of Meghan's relationship with her father was "the final straw in a campaign of negative, nasty coverage about her".
Harry and Meghan, 41, sensationally quit royal life in early 2020 and moved to North America, from where they have launched a series of broadsides about the royal family.
In the first three episodes released last Thursday, the couple -- also known as the Duke and Duchess of Sussex -- criticised the royal family for "unconscious" racial bias.
They accused the palace of failing to protect Meghan and Harry's mother Diana against tabloid excesses.
Most of their criticisms were directed at the media.
But direct mention of William, 40, in the latest trailer confirmed suspicions that the more pointed criticisms may have been saved for last.
Daily Mail royal correspondent Rebecca English said "the gloves are off" while her counterpart at ITV, Chris Ship, said, "It's getting dirty."
Suggestions that his brother and his entourage were to blame for the negative coverage that Harry and Meghan received was "a dramatic escalation", he added.
- 'Business as usual' -
So far the palace has declined to respond to the programme and disputed claims by Netflix that they were approached to comment on the contents of the series.
Senior royals, led by Harry's father King Charles III, are expected to attend a Christmas carol concert on Thursday in a demonstration of "business as usual".
But commentators suggested they may be forced to act if criticism gets personal, as Harry and Meghan faced calls to give up their royal titles -- or have them removed.
Last week, Harry appeared to take a dig at his older brother and his wife Catherine.
"With many people in the family, especially the men, there can be a temptation or an urge to marry someone who would fit in the mould," he said.
Netflix said last week's episodes recorded 81.55 million viewing hours globally -- "the highest view hours of any documentary title in a premiere week".
Several British newspapers said the docuseries was an effective declaration of "war" by the couple.
They have already faced claims of trying to sabotage William's first trip to the United States as heir with the release of the first trailer.
A December 9 YouGov poll indicated that the docuseries, which comes three months after the death of Queen Elizabeth II, had further dented Harry and Meghan's popularity in the UK.
Harry and Meghan saw their negative ratings with the British public fall to -26 percent and -39 percent after the programmes, from -13 percent and -32 percent before.
Only Harry's disgraced uncle Prince Andrew, who earlier this year settled a US civil claim for sexual assault out of court without admitting liability, was less popular.
He had a -79 percent rating.