The Duke of Sussex’s unprecedented statement unleashing pent-up fury against the British tabloid press over its treatment of his wife may prove counter-productive, royal commentators have claimed.

The statement, which Harry is understood to have personally penned, was released on the couple’s official website as it was announced on Tuesday that the Duchess of Sussex is suing the Mail on Sunday over an allegation it unlawfully published a private letter she sent to her estranged father, Thomas Markle.

The couple is privately funding the legal action, with any proceeds being donated to an anti-bullying charity.

A Mail on Sunday spokesman said it stood by the story it published and would defend the case “vigorously”.

Why is Meghan suing the Mail on Sunday? Read more

In a statement taking aim far beyond the Mail on Sunday, Harry accused tabloids of waging a “ruthless” campaign of vilification of Meghan, and comparing her treatment to that of his mother, Diana, Princess of Wales.

The timing of Harry’s intervention meant it dominated the last two days of a tour funded by the Foreign Office and designed to throw a spotlight on issues and concerns the government wished to highlight.

“It is absolutely extraordinary,” said royal biographer, Penny Junor. “People can understand Harry taking issue with someone printing a private letter. But his statement went far beyond that.

“It is as though he has got months of pent-up rage in him. I really, really question the wisdom of taking on the media in this way.”

The BBC’s royal editor, Nicholas Witchell, said the timing was “curious” given the visit has been a “considerable success” and had lifted the couple’s reputation “after a series of mis-steps involving private jets and expensive property renovations”. The media commentator Roy Greenslade told Radio 4’s Today programme: “Is [Harry] taking a sledgehammer to crack a nut here? I think he may well find that this is counter-productive.”

Palace sources indicate the timing of the announcement was based on specific legal advice. It is understood the claim was filed on Sunday 29 September, and processed by the court on Monday. The particulars of the claim would need to be served within 14 days, and within another 14 days, the claims documents would be accessible to the public.

While this may explain the timing on the announcement of legal action, it does not, however, fully explain the timing or content of Harry’s statement.

Law firm Schillings, acting for the Duchess, has filed a high court claim against the paper and its parent company – Associated Newspapers – over the alleged misuse of private information, infringement of copyright and breach of the Data Protection Act 2018.

Harry has also accused the paper of misleading readers by strategically omitting paragraphs, sentences and specific words – “to mask the lies they had perpetrated for over a year”. The newspaper denies this.

“The paparazzi in Diana’s day wanted to elicit a negative reaction, wanted her to burst into tears or lash out,” said Stephen Bates, author of Royalty Inc . “I think the coverage has been pretty snippy about Meghan, sometimes with reasonable cause, private jets and all that. But she is in no way comparable to Diana, because she has been much better shielded, and she’s in a much less vulnerable position, and a much less vulnerable person.”

PR consultant Mark Borkowski said the statement risked the pair being “a little too open about what they think about the media”.

“The royals normally keep the media at arm’s length but this is not an arm’s length move. Harry is determined not to play the media game. There is no charm left, this is an open declaration of war,” he told PA. “He has drawn a line in the sand and that line has been crossed. There will be a lot of people who support him, but he will also be losing a lot of friends.”

It is not the first time Harry has moved to defend Meghan’s over her treatment by the media. In November 2016, he confirmed he was dating the US actor and lashed out at the “wave of abuse and harassment” she had faced from publications.

His communications secretary Jason Knauf outlined the difficulties Meghan had experienced since news of their relationship broke in a statement which said she had been “subject to a wave of abuse and harassment”.

