Judge Timothy Fancourt said phone hacking continued "to some extent" during the Leveson Inquiry into media standards in 2011 and 2012.

The Duke of Sussex's case was "proved in part", with 15 of the 33 articles presented in court found to be the product of phone hacking or other unlawful information gathering, the judge ruled.

Follow latest: Prince Harry v Mirror group

In a statement, Prince Harry said the ruling was "vindicating and affirming" and took aim at senior executives and editors including Piers Morgan - who was in charge at the Daily Mirror from 1995 to 2004.

Judge Mr Justice Fancourt ruled that Morgan knew about phone hacking at the paper.

"The court has found that... editors including Piers Morgan clearly knew about or were involved in these illegal activities," Prince Harry's statement said.

He said the Duke's phone was probably only hacked to a modest extent and was "carefully controlled by certain people" from the end of 2003 to April 2009.

But he added that there was a tendency by the Duke to assume everything was a result of hacking.

The judge awarded Prince Harry a total sum of £140,600. The sum was aggregated as directors of the newspaper group knew and "turned a blind eye and positively concealed it".

In a statement read by his lawyer David Sherborne, Prince Harry said: "This case is not just about hacking, it is about a systemic practice of unlawful and appalling behaviour followed by cover-ups and destruction of evidence, the shocking scale of which can only be revealed through these proceedings.

Since the claim was brought, the prince said "defamatory stories and intimidating tactics have been deployed against me and at my family's expense".

"I am happy to have won the case, especially as this trial only looked at a quarter of my entire claim," he said.

"Today's ruling is vindicating and affirming. I have been told that slaying dragons will get you burned, but in light of today's victory and the importance of doing what is needed for a free and honest press, it is a worthwhile price to pay."

Coronation Street actor awarded damages

Meanwhile, Coronation Street actor Michael Le Vell was awarded £31,650 in damages after the judge found four out of the 27 articles presented to court were the product of phone hacking or unlawful information gathering.

Mr Justice Fancourt said the claims of soap actress Nikki Sanderson and the ex-wife of comedian Paul Whitehouse, Fiona Wightman, were barred because times for their claims had expired.

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But he found that nine articles relating to Ms Sanderson and one article related to Ms Wightman were the product of unlawful information gathering.

The judge found there was "some unlawful activity" at the newspaper group in 1995, and "widespread" unlawful information gathering from 1996.

The practice was "widespread and habitual" from 1998 onwards, the judge said, while phone hacking "remained an important tool in the climate of journalism" at all three papers - the Daily Mirror, the Sunday Mirror and Sunday People - from 2006 to 2011.

But phone hacking and unlawful information gathering were then done "in a more controlled way" and not as habitually as before 2006.

Private investigators 'integral part' of Mirror newspapers

Unlawful information gathering involving private investigators hired by the Mirror Group "reduced in amount" between 2006 and 2011 but "remained extensive" throughout the period.

Some 11 private investigators - out of 51 complained about in the case - were used "very substantially" by journalists and editors and an "integral part of the system" that existed at the three papers.

Two directors knew about phone hacking

Meanwhile, two directors at MGN - Paul Vickers and Sly Bailey - knew about phone hacking but did not inform the rest of the board, the judge found.

"It was concealed from the board, Parliament, the public, the Leveson Inquiry," the judge said.

A spokesperson for Mirror Group said: "We welcome today's judgment that gives the business the necessary clarity to move forward from events that took place many years ago.

"Where historical wrongdoing took place, we apologise unreservedly, have taken full responsibility and paid appropriate compensation."

'Extraordinary cover-up'

Hacked Off, the campaign group established in 2011 after the phone hacking revelations, said in a statement that today's judgment "lays bare the extraordinary cover-up which has taken place at Mirror Group Newspapers over the last two decades".

"It paints the picture of a rotten corporate culture, desperate to escape accountability at all costs. Other newspaper groups will also be looking over their shoulders, as this judgement shows that justice may yet catch up with them all," the group's chief executive Nathan Sparkes said.

The Duke of Sussex had claimed journalists at its titles were linked to controversial methods including phone hacking, so-called "blagging" and the use of private investigators for unlawful activities.

The civil trial at the High Court ended in June after seven weeks and saw Prince Harry appear in the witness box - the first time a senior royal has given evidence in a courtroom since the 19th century.