Giving evidence at the UK High Court in London yesterday, the singer also described his claim against the newspaper’s publisher as containing “the most horrendous things in the world that you could ever suffer, from a privacy point of view” in an angry outburst.

Mr John and his husband David Furnish are part of a group of seven high-profile figures, including Prince Harry, actress Elizabeth Hurley and campaigner Doreen Lawrence, bringing legal action against Associated Newspapers Limited (ANL).

The couple allege 10 articles about them between 2000 and 2015 were based on unlawful information gathering, including unlawfully obtained medical information and landline tapping.

ANL has strongly denied wrongdoing, with lawyers for the publisher previously telling the court that the claims made by Mr John and Mr Furnish are “unsupported by any evidence before the court and utterly baseless”.

Appearing in a green suit, blue shirt and tie via videolink on the 15th day of the trial, Mr John told the hearing in London that he and his husband took legal action against the publisher of the Daily Mail because they were “outraged”.

Speaking of the 10 articles over which their claim has been made, Catrin Evans KC, for Associated Newspapers Limited, said: “It is true you did not complain at the time that they were published, about any of them.”

John replied: “We did not know the extent of the seriousness of what had gone on. When we knew the seriousness of what had gone on, we took action, because we were outraged.”

In a witness statement provided shortly after Mr John began giving his oral evidence, the singer-songwriter said: “There have been many unacceptable features of this claim for David and me.

“The exploitation of love, connection, trust and bonds to find out information shared in confidence.

“The secrecy and invisibility of such evil acts that we never had a chance of catching or detecting or putting a stop to, which we would have done immediately had we known what was happening.

“The violation of our home and the safety of our children and loved ones.

“But from a personal level, I have found The Mail’s deliberate invasion into my medical health and medical details surrounding the birth of our son Zachary abhorrent and outside even the most basic standards of human decency.”

Mr John also described in his written evidence how it had been “truly sickening” for him and Mr Furnish to see documents in their legal claim against the Daily Mail’s publisher.

In written submissions, Antony White KC and Ms Evans KC, both for ANL, said the social circles of most of the group of household names bringing the claims were “leaky”.

They continued: “Their friends, and friends of friends or associates, did regularly provide information to the press about the claimants’ private lives, for obvious reasons on a confidential basis.”

The barristers later said that Mr John’s spokesman at the time “regularly provided the media, including Associated journalists, with information about their lives”, including health information.

Mr John told the court that the spokesman “no longer works for us”.

The court was previously told that Mr John and Mr Furnish felt the safety of their children had been “violated” by alleged unlawful news-gathering, including the alleged “stealing” of Zachary’s birth certificate before the couple had received a copy.

In written submissions, ANL’s lawyers said that the article was “entirely legitimately” sourced from previously published reports of the child’s birth, information from the local registrar’s office as well as a statement from a surrogacy agency.

Ms Evans suggested information had been put into the public domain before the Mail article.

In response, Mr John described the birth of Zachary as like an “army manoeuvre”, adding: “We kept it quiet, which was a miracle considering who we are.”

Mr John appeared in court a day after Mr Furnish gave evidence.

The trial before Mr Justice Nicklin has been adjourned until 10.30am on Monday, and is due to conclude in March, with a judgment in writing expected at a later date. (© The Independent)