(AFP) - Prince Harry on Tuesday testified he had suffered lifelong "press invasion" and that some media had blood on their hands, as he became the first British royal in more than 100 years to give evidence in court.

The younger son of King Charles III accuses Mirror Group Newspapers (MGN) -- publisher of The Mirror, Sunday Mirror and the Sunday People tabloids -- of illegal information gathering, including phone hacking.

In a much-anticipated appearance in the witness box at London's High Court, Harry said he had been the victim of relentless and distressing media intrusion "most of my life up until this day".

"How much more blood will stain their typing fingers before someone can put a stop to this madness," the 38-year-old added in a lengthy witness statement released.

"You're then either the 'playboy prince', the 'failure', the 'dropout' or, in my case, the 'thicko', the 'cheat', the 'underage drinker', the 'irresponsible drug taker', the list goes on.

"As a teenager and in my early 20s, I ended up feeling as though I was playing up to a lot of the headlines and stereotypes that they wanted to pin on me... It was a downward spiral," he said, calling the reporting "utterly vile".

During cross-examination by MGN's lawyer Andrew Green, Harry admitted that he had no recollection of reading the majority of the articles -- many around two decades old -- that he was complaining about.

But he called them "incredibly invasive" and taken as a whole they had made him acutely paranoid and ruined his relationships.

"Friendships were lost entirely unnecessarily," the prince noted.

- 'Total speculation' -

The case is Harry's latest legal battle with the press since he stepped down from royal duties in early 2020 and relocated to California with his American wife Meghan.

It centres on claims that MGN's tabloids broke the law to obtain stories about Harry and other claimants, including two TV soap opera actors and the ex-wife of a comedian.

Harry's legal team has submitted that "industrial scale" illegal activities were happening at the publisher and had been approved by senior executives.

At the May 10 start of the trial, MGN apologised and admitted to "some evidence" of unlawful information gathering, including for a story about Harry.

But it denied voicemail interception and also argued that some claims had been brought too late.

Dressed in a dark suit and tie, the Duke of Sussex -- as he is formally known -- began giving evidence shortly after 0930 GMT, swearing an oath on the Bible.

He remained in the witness box through the first of two scheduled days of testimony, with the court adjourning some seven hours later following multiple breaks.

Harry was questioned about various aspects of the 33 tabloid stories being considered, covering everything from ex-girlfriends to royal family relations.

Green, who sought to show other newspapers had often run similar stories before the MGN titles, accused him of "total speculation" on several occasions over hacking claims.

While Harry repeatedly conceded he could "see the similarities" between the articles, the prince remained steadfast that specific details in MGN ones were "suspicious".

- 'Rock bottom' -

Harry -- fifth in line to the throne -- has had a turbulent relationship with the press and holds the media responsible for the death of his mother, Princess Diana, in a 1997 Paris car crash while being pursued by paparazzi.

In television interviews and his explosive memoir "Spare", released in January, Harry hit out at other royals, accusing them of colluding with the press.

In court filings unveiled in April, Harry claimed the royal family as an institution had struck a "secret agreement" with one UK publisher that had prevented him from suing, to avoid a royal entering the witness box.

He also alleged the monarchy wanted to prevent the opening of a "Pandora's Box" of negative coverage that could tarnish the royal brand.

Although the royal family are normally scrupulous about staying out of politics, Harry also hit out at the government Tuesday.

"On a national level, at the moment, our country is judged globally by the state of our press and our government, both of which I believe are at rock bottom," he said in his witness statement.

"Democracy fails when your press fails to scrutinise and hold the government accountable, and instead choose to get into bed with them so they can ensure the status quo."

The last time a royal gave evidence in court was in the 1890s when the future king Edward VII took the stand in a slander trial.

© Agence France-Presse