Former Daily Mirror editor Piers Morgan has said he “never hacked a phone or told anyone else to hack a phone”, after a High Court judge accepted evidence that he knew journalists were involved in the practice.

Speaking outside his home in London on Friday, the broadcaster said he had “zero knowledge” of an article about the Duke of Sussex published in his time as editor which may have involved unlawful information gathering.

His comments came after a ruling over phone-hacking claims brought against the newspaper’s publisher, Mirror Group Newspapers (MGN).

Mr Justice Fancourt concluded “there can be no doubt” that editors of MGN’s titles knew about voicemail interception, but did not tell the company’s board or chief executive about it.

Mr Morgan was The Daily Mirror’s editor between 1995 and 2004.

The judge ruled that unlawful information-gathering was “widespread” at MGN publications The Daily Mirror, The Sunday Mirror and The People from 1996 onwards, and phone hacking became “habitual” from 1998.

The judge’s findings came after a trial of cases brought against the publisher, including a partially successful claim by the Duke of Sussex.

Mr Morgan said of the article relating to Harry: “To be clear I had then, and still have, zero knowledge of how that particular story was gathered.

“All his other claims against the Daily Mirror under my leadership were rejected.”

He added: “I also want to reiterate, as I’ve consistently said for many years now, I’ve never hacked a phone or told anyone else to and nobody has provided any actual evidence to prove that I did.”

The TalkTV host described those giving evidence in the Duke of Sussex’s High Court case as “old foes of mine with an axe to grind”, singling out author Omid Scobie and journalist Alastair Campbell.

He said he was not called as a witness for the trial earlier this year, nor asked to provide a statement, which he “would have very happily agreed to do”.

“Nor did I have a single conversation with any of the Mirror Group lawyers throughout the entire legal process,” Mr Morgan said.

“So I wasn’t able to respond to the many false allegations that were spewed about me in court by old foes of mine with an axe to grind, most of which, inexplicably, were not even challenged in my absence by the Mirror Group counsel.”

Mr Morgan claimed Mr Scobie had “lied about me in court” and also alleged Mr Campbell was “another proven liar”.

Harry alleges 147 stories from 1996 to 2010, published by MGN titles, used information obtained through unlawful means, such as phone hacking.

Some 33 articles, dated between 1996 and 2009, were selected for examination during the trial, with the judge finding 15 were the product of hacking or unlawful activity.

In his ruling, Mr Justice Fancourt said he accepted the evidence of Mr Scobie, who said Mr Morgan was told about a use of phone hacking.

The court previously heard that Mr Scobie did work experience at The Daily Mirror in spring 2002, and overheard Mr Morgan being told that information relating to Kylie Minogue and her then-boyfriend James Gooding had come from voicemails.

The judge said an article about them in May 2002 carried the byline of James Scott “who was one of the showbiz journalists and a known phone hacker”.

He added that there was a £170 invoice from private investigator firm TDI to Mr Scott from earlier that month, for “extensive inquiries carried out on your behalf”, and the mobile telephone numbers of both people were in Mr Scott’s PalmPilot.

“These documents bear out Mr Scobie’s recollection,” the judge said.

He said Mr Scobie was “pressed hard about the likely veracity of these accounts” while giving evidence, adding: “I found Mr Scobie to be a straightforward and reliable witness, and I accept what he said about Mr Morgan’s involvement in the Minogue/Gooding story.

“No evidence was called by MGN to contradict it.”

The judge also said Mr Campbell’s evidence that private investigators were instructed to obtain confidential information about his finances was “wholly credible”.

He said Mr Morgan “would have known about the Campbell attempted sting”.

The judge said he accepted “without hesitation” evidence from David Seymour, who was group political editor of The Daily Mirror from 1993 to 2007, who told the trial that he regarded Mr Morgan as “unreliable and boastful, who was apt to tell untruths when it suited him”.

Mr Seymour said he was told by a colleague that Mr Morgan had “taunted” the chief executive of BT at a lunch in 2002, where the then chairman of MGN’s parent company was present, telling him that he would need to tell his customers to change their phone PINs from factory settings.

This evidence was challenged by MGN lawyers with the suggestion that “it would have been the last thing that Mr Morgan would have done if he was involved in phone hacking”, the judge said.

But Mr Seymour said Mr Morgan was “an extremely boastful person and he would have really enjoyed saying to the chairman, chief executive of BT: aren’t we clever”.

The judge said: “Mr Seymour agreed that Mr Morgan was no fool, but said that he behaved foolishly at times, and that he felt this showed that Mr Morgan knew that his journalists were involved in phone hacking.

“Mr Seymour struck me as a man of intelligence and integrity. I accept his evidence without hesitation.”

The judge also said information from a private investigator firm was “clearly” the source of an article that claimed Prince Michael of Kent, the late Queen’s cousin, was £2.5 million in debt to a Coutts & Co bank, which was front page of The Daily Mirror in January 1999.

He said Southern Investigations, a firm that issued invoices linked to the story, was “conducting criminal activities”, with Gary Jones, a journalist behind the story, being “a regular customer”.

When Prince Michael raised a legal complaint against MGN, Mr Morgan said the allegation came from “an impeccable source who has an intimate knowledge” of the prince’s finances.

But the judge said MGN’s case that “confidential sources” were involved in the story was “hopelessly unrealistic” and “invented”.

The publisher later settled Prince Michael’s claim, agreeing to publish an apology and pay his legal costs, the court was previously told.

Mr Justice Fancourt was told the complaint was also handled by Martin Cruddace, The Daily Mirror’s in-house lawyer at that time, and then group legal director Paul Vickers.

The judge said the episode “demonstrates that the editor, a member of the legal department and Mr Vickers, a board member, knew in 1999 that journalists in the Daily Mirror were conducting unlawful information gathering, using very dubious private investigators”.

Mr Justice Fancourt also found that unlawful activity was “concealed” from Parliament, shareholders and the public, as well as the board overseeing MGN.

In his summary of his ruling, he said: “The board as a whole was not told about it.

“That was because the editors of the three newspapers, the editorial managers of the company and [chief executive Sly] Bailey and Mr Vickers did not report what they knew, or suspected, to the board.

He added: “The likelihood of extensive illegal activity should have been investigated properly by Ms Bailey and Mr Vickers, at the latest in early 2007, but it never was.