A BBC documentary is to resuscitate painful allegations the Duke and Duchess of Sussex did not receive enough support while in the Royal family, amid fears the appearance of their lawyer on the controversial show will make it a one-sided narrative.

The second episode of Princes and the Press is expected to revisit claims the Duke of Sussex did not receive the same support in dealing with an intrusive press as the Duke of Cambridge would have done, in scenes which will infuriate former and current palace staff.

Allies of the Sussexes, including their biographer interviewed in the programme, have consistently claimed the couple were not defended against stories in the tabloid media.

Those who worked for them object to the claims, believing aides did their utmost to protect them in difficult circumstances.

The two-part documentary, presented by Amol Rajan, has caused upset at the three households of Buckingham Palace, Clarence House and Kensington Palace, which released a rare joint statement calling its contents “overblown and unfounded”.

Reported anger at the BBC

A carol concert starring the Duke and Duchess of Cambridge was offered to ITV over the BBC reportedly amid anger at the corporation. 

Aides believe programme-makers have not offered them a proper right of reply, claiming allegations were not put to them in full ahead of broadcast.

They have not engaged with the show, arguing it would give undue credibility to newspaper stories mentioned in it which they have never commented on before.

The Duchess of Sussex, in contrast, has authorised her lawyer Jenny Afia to appear on camera, to defend her against accusations of bullying former staff in the Royal Household and to discuss her recent court case against the Mail on Sunday.

The final episode, as well as a podcast focusing specifically on Prince Harry, Meghan and the media, will air on Monday and examines the period of 2018 to 2021.

It promises to include details of a “tumultuous time for the royals” including the birth of Archie Mountbatten-Windsor, the royal tours of the Sussexes and the Cambridges, and the “circumstances surrounding the Sussexes’ decision to step down from their senior royal roles”.

Prince Harry and Meghan’s various legal cases discussed

It will also detail the various legal cases launched by Prince Harry and Meghan, and “considers the impact Princess Diana’s experiences with the press and broadcasters had on her sons” – including the Martin Bashir scandal.

The programme is due to air just as the Prince of Wales is in Barbados to witness it become a republic, in a landmark ceremony.

The first episode included claims – strongly denied – that briefings about members of the Royal family came from within the palace itself

Former BBC Royal Correspondent Peter Hunt claimed no serious briefing between the three households would occur without the “approval of the principal”, saying: “So you have to assume they’ve done it with the knowledge of whoever they were working for.”

A joint statement provided by Buckingham Palace, Clarence House and Kensington Palace in response to the show said: “A free, responsible and open press is of vital importance to a healthy democracy.

“However, too often it is overblown and unfounded claims from unnamed sources that are presented as facts and it is disappointing when anyone, including the BBC, gives them credibility.”

A BBC spokeswoman said: “The programme is about how royal journalism is done and features a range of journalists from broadcast and the newspaper industry.”