Daily Mirror accused of hacking Diana’s phone during friendship with Michael Barrymore

The phone of Diana, Princess of Wales was allegedly hacked by Piers Morgan’s Daily Mirror in an attempt to obtain details about her secret meetings with the comedian Michael Barrymore.

The high court heard that Diana had regularly talked to Barrymore in the months before her death, at a time when they were two of the most famous people in Britain. The television presenter was “struggling with coming out as gay”, as well as dealing with an addiction to alcohol and drugs.

On Monday, a phone-hacking trial heard extracts from a letter in which Diana offered to support Barrymore, who was one of the nation’s leading television stars. In one letter, sent in early 1997, the princess provided her phone number and wrote: “Dear Michael. What joy it was to finally meet you tonight. I did want to emphasise that I’m here for you – whenever.

“It’s very easy to pop round and see you or please telephone now you have my number. You’re doing just fine and believe me, I know. So take great care and lots of love from Diana.”

Months later, Diana wrote again to say she was “devastated” that details of their supposedly secret meetings had been obtained by the Daily Mirror. She apologised to Barrymore for the leak, expressed her disgust with the tabloid press, and said she did not know how the news had come out, given “nobody knew about our conversations”. The court heard that Barrymore did not reply to this letter, highlighting the “isolation” caused by press intrusion.

David Sherborne, the barrister who is acting for Diana’s younger son, Prince Harry, in the trial against Mirror Group Newspapers (MGN), said the simple explanation was that journalists working for the Daily Mirror had hacked Diana’s voicemails.

Related: What’s at stake for Prince Harry as he gives evidence in phone-hacking trial?

The lawyer also suggested the Daily Mirror’s then editor, Piers Morgan, was disingenuous when he later wrote in his autobiography that he had “heard rumours” about a friendship between Diana and Barrymore.

Sherborne said that how Morgan had “heard” the rumours “was obvious”. The lawyer alleged the real reason the editor knew so much about Diana’s friendship with Barrymore was because “the Mirror had been listening in to her messages”.

Morgan has denied knowingly commissioning or using material from phone hacking.

The allegations were made in the ongoing phone-hacking trial against Mirror Group Newspapers. On Monday the court started to deal with the specifics about Harry’s case against MGN.

The court has spent three weeks hearing evidence about the general culture at the Daily Mirror, Sunday Mirror and People. Harry alleges he was the victim of phone hacking and other illegal information-gathering tactics by the outlets.

Sherborne began outlining the 33 Mirror articles about Harry that are being analysed as part of the case, with headlines such as “Diana so sad on Harry’s big day”, arguing that many showed the “telltale signs” of illegal information-gathering.

The Mirror insists that all articles were obtained through legal means, such as sources providing information and press officers briefing stories.

The prince had been expected to appear in court on Monday but did not turn up, after staying in Los Angeles to attend his daughter’s second birthday party.

This angered the judge, who had requested Harry be available to give evidence on Monday afternoon, only to be informed that the prince had stayed late in California so he could celebrate with his daughter, Princess Lilibet.

The Mirror’s lawyers accused Harry of “wasting time” by failing to be ready to give evidence as a result of catching a flight from California only on Sunday evening.

Harry is now expected to start giving evidence on Tuesday morning.