Former NoW royal editor Clive Goodman told the phone-hacking trial he was sent the 1992 book because she was looking for “an ally” in the press.

She wanted to show the forces “ranged against her” in a “bitter situation” with the Prince of Wales, he said. Mr Goodman is accused of paying police for royal phone books, which he denies.

The BBC’s home affairs correspondent Tom Symonds, at the Old Bailey, said it was “another extraordinary revelation from this extraordinary trial”.”

‘Tough time’

Princess Diana, who separated from Prince Charles in 1992 after 11 years of marriage, sent the book to the newspaper and it “worked its way into my pigeonhole”, Mr Goodman told the court.

“She was at the time going through a very, very tough time,” he said.

“She told me she wanted me to see this book, she wanted me to see the scale of her husband’s staff and household, compared to the scale of hers.

“She was in a very bitter situation with the Prince of Wales at the time, she felt she was being swamped by the people close to him.

“She was looking for an ally and to take him on to show the kind of forces that were ranged against her.”

Mr Goodman said the princess later called him to check he had received it.

Princess Diana and Prince Charles divorced in 1996. She was killed in a car crash in Paris a year later.