“These tactics are not new. In fact,they’ve been going on for too long without consequence,” she said.

“For these outlets,it’s a game. For me and so many others it’s real life,real relationships and very real sadness. The damage they have done and continue to do runs deep.

“The world needs reliable,fact-checked,high quality news. WhatThe Mail on Sunday and its partner publications do is the opposite. We all lose when misinformation sells more than truth,when moral exploitation sells more than decency,and when companies create their business model to profit from people’s pain.”

The controversial royal couple last year announced they would end all co-operation with four tabloids -The Daily Mail,The Sun,The Daily Mirror and The Express -despite insisting they valued a free press.

Lawyers forThe Mail on Sunday had argued to the court that there was legitimate public interest in the conduct and standards of behaviour of the royal family. The public interest extended to their personal and family relationships because “those are integral to the proper functioning of the monarchy”,they said.

The duchess claimed in her statement that the court had delivered a “comprehensive win on both privacy and copyright” elements of the lawsuit however Justice Warby said the question of copyright should go to a limited trial.

The trial will determine whether the duchess was the sole author of the letter or whether input from Kensington Palace’s then communications secretary Jason Knauf might make him a co-author.

Thomas Markle would likely not be a witness over the copyright matter but he could have given evidence against his daughter had the privacy component of the case gone to trial.

“We now know - and hope it creates legal precedent - that you cannot take somebody’s privacy and exploit it in a privacy case,as the defendant has so blatantly done over the past two years,” the duchess concluded in her statement.

She thanked Prince Harry,mother Gloria Ragland and wider legal team.

An Associated Newspapers spokesperson said:“We are very surprised by today’s summary judgment and disappointed at being denied the chance to have all the evidence heard and tested in open court at a full trial.

“We are carefully considering the judgment’s contents and will decide in due course whether to lodge an appeal.”

Nigel Tait,a partner at high-profile British law firm Carter-Ruck who has acted for Elton John,Simon Cowell,Liam Gallagher and other celebrities in fights with the press,toldThe Sydney Morning andThe Age last year that Associated Newspapers may have to pay the Duchess £1 million ($1.78 million) in damages and costs if they lost the case.

But he said the newspaper group might not consider that outcome a loss.

“The editors will know that this case is going to attract world attention and that it will be good copy for them,” he said.

“It may be commercially worth it to them to spend £1 million fighting a case they lose,if they can make some inroads and land some punches.”