Meghan Markle is suing the Mail on Sunday newspaper while an impassioned Prince Harry has revealed his wife’s private suffering at the hands of the UK tabloid media.

In a detailed personal statement, the Duke of Sussex invoked his late mother, Princess Diana, saying the couple’s decision to take legal action against “propaganda” had been “many months in the making”.

It came as he watched the press pack wage a “ruthless campaign” with “lie after lie” against Meghan.

“I’ve seen what happens when someone I love is commoditised to the point that they are no longer treated or seen as a real person,” Harry, 35, wrote.

“I lost my mother and now I watch my wife falling victim to the same powerful forces.”

Diana died in 1997 when her car crashed in a Paris tunnel after being pursued by paparazzi.

“Ultimately it will be the courts that decide whether Meghan has done the right thing by launching legal action,” Dr Mitchell Hobbs, lecturer in media and public relations at the University of Sydney, told The New Daily.

“But it is certainly an understandable response.

“And as the phone-hacking scandal showed, some British tabloids have gotten it wrong on questions of privacy and accuracy before. Time will tell if the Mail on Sunday have done so this time.”

Meghan learns about a ‘wellbeing economy’ in Johannesburg on Tuesday. Photo: Instagram

Meghan, 38, has taken issue with the publication of a private letter to her father Thomas Markle, which Harry said had been manipulated to distort the truth.

The attacks against his wife had escalated over the past year, during her pregnancy and while raising their son Archie, five months.

“There is a human cost to this relentless propaganda, specifically when it is knowingly false and malicious, and though we have continued to put on a brave face … I cannot begin to describe how painful it has been,” he wrote.

Until now the couple has been able to correct “continual misrepresentations” but decided to “stand up to this behaviour because it destroys people and destroys lives”, Harry said.

“It is bullying, which scares and silences people. We won’t and can’t believe in a world where there is no accountability for this.”

Harry, who is winding up an official tour of Africa with his wife and son, said Meghan had been vilified almost daily for the past year.

“They have been able to create lie after lie at her expense simply because she has not been visible while on maternity leave,” he wrote.

“She is the same woman she was a year ago on our wedding day, just as she is the same woman you’ve seen on this Africa tour.”

“Arch meets Archie!” captioned the Sussexes of their boy’s face-to-face encounter with Archbishop Desmond Tutu in South Africa. Photo: Instagram

The long-time mental health advocate added that he had been a silent witness to his wife’s private suffering for too long.

“To stand back and do nothing would be contrary to everything we believe in,” Harry said.

He added the Sussexes’ legal action hinges on one incident, when the “contents of a private letter were published unlawfully” to “manipulate”, and give fuel to “a divisive agenda.”

Harry and Meghan share a private moment. Photo: Instagram

Harry first publicly defended Meghan in 2016, when his romance with the then-Suits actor was in its early stages.

In an unprecedented authorised statement, Harry’s communication secretary said Meghan had been subject to a “wave of abuse and harassment” including comments with “racial” undertones.

Harry’s brother Prince William and his wife Kate Middleton, both 37, have also stood up to tabloids.

In 2017 a court awarded the Cambridges $163,000 in damages after a French magazine published long-lens images of the duchess sunbathing topless on a private terrace.

The Mail on Sunday could not immediately be reached for comment.