A private investigator has apologised for targeting the phone of a former girlfriend of the Duke of Sussex and admitted he helped “rob” him of his teenage years.

Gavin Burrows told the BBC there had been a “ruthless” culture in parts of the media in the early 2000s, when he said Chelsy Davy’s phone had been under surveillance.

He told a BBC documentary called The Princes And The Press there was a much greater interest in Harry than his brother, the Duke of Cambridge, when he began working for the now defunct News of the World in 2000.

Editors told him putting Harry on the front page sold more copies of newspapers than William.

“As explained to me by a couple of editors, Harry had basically become the new Diana,” he said.

The BBC says Mr Burrows is a witness in legal cases against the News of the World and The Sun, but that his claims are yet to be tested in court and are strongly disputed.

Harry brought legal proceedings against News Group Newspapers (NGN) and Reach – formerly Mirror Group Newspapers – in 2019, just days after it was announced that the Duchess of Sussex was suing the Mail on Sunday after it published a letter she wrote to her father.

Mr Burrows told the BBC documentary: “There was a lot of voicemail hacking going on, there was a lot of surveillance work on her phones, on her comms.

“Chelsy would brag to her friends when she was going to see him.”

He said investigators were interested in her medical records, ex-boyfriends and details of her education.

Mr Burrows said he was “very sorry” and explained: “I was greedy, I was into my cocaine, and I was living in a fake state of grandeur.”

He added there was a “ruthless” culture in the media, saying: “They’ve got no morals – they absolutely have got no morals.”

Mr Burrows went on to say: “I was basically part of a group of people who robbed him (Harry) of his normal teenage years.”

The News of the World folded in 2011 after details emerged of extensive phone hacking at the newspaper.

The paper’s publishers, News Group Newspapers, have settled several claims brought against it by a number of high-profile celebrities, including Hugh Grant and David Tennant, but has never made any admission of liability in relation to allegations involving The Sun.

The High Court heard last year that a journalist at The Sun was sent Ms Davy’s phone billing data, which had been illegally obtained, by another private investigator.

Documents disclosed to the claimants’ legal team were said to reveal a South Africa-based private investigator, Mike Behr, sent Ms Davy’s phone records to The Sun’s then-royal correspondent, Duncan Larcombe, in a May 2005 email titled “March records”.

A spokesperson for Harry and Meghan’s Archewell Foundation declined to comment. NGN has been approached for comment.