The News of the World hacked the phones of Milly Dowler's parents so that they could spy on their "moment of immense grief", the Leveson inquiry was told today.
Bob and Sally Dowler tried to cope with their loss by re-tracing their daughter's final steps before she was murdered - but the date and time of the trip were known and their anguish was published to the world.
Barrister David Sherborne said the Dowlers were betrayed in a "terrible intrusion" , adding: "Probably there are no words which can adequately describe how despicable this was. The Dowlers' story is just one of those you will hear.
"The Dowlers were subjected to terrible intrusion, intrusion at a moment of immense grief. They are by no means alone.
"It was a private act, a very private moment. But it was a photo opportunity too good to resist. Someone at the press found out they were undertaking that last walk on that particular day at that particular time. The News of the World published an article under the headline 'the longest walk', complete with pictures of the distressed couple."
Milly, 13, was murdered by club doorman Levi Bellfield who snatched her while she was walking home from school in Walton-on-Thames nine years ago.
The News of the World was engulfed in scandal when it emerged that they had hacked Milly's phone during the hunt for her - raising hopes that she was alive.
Mr Sherborne said that Mr and Mrs Dowler would reveal how "euphoria" turned to be false when they realised Milly's voicemail had been hacked and she was not alive.
On the third day of the inquiry into media ethics and practices, Mr Sherborne also said that victims of the phone hacking scandal were subject to a range of "tawdry" behaviour in the search for newspaper stories.
The lawyer, who is representing 51 clients including JK Rowling and Hugh Grant at the inquiry, said the charge sheet included illegally accessing private information, breach of confidences, vilification and bullying.
He said: "It may take some time today to outline the true unvarnished extent of the tawdry journalistic trade we now have in this country, particular with the publication of personal information about people's private lives - information that in some cases has been rightly denied to the press as a matter of law."
Mr Sherborne's clients also include the families of Madeleine McCann and Christopher Jefferies, who was wrongly suspected of the murder of Joanna Yeates in Bristol.
The Dowler family is expected to be among the 21 witnesses to give evidence to Lord Justice Leveson's inquiry from Monday.
Mr Dowler was today again watching proceedings from the public gallery, as was former Formula 1 boss Max Mosley.
Mr Sherborne said Mr Mosley, who won £60,000 damages from the News of the World after it breached his privacy by publishing a story headlined "Formula One boss has sick Nazi orgy with five hookers", would give evidence next week.
He said the paper's chief reporter, Neville Thurlbeck, had threatened the five women in a bid to get them to co-operate. Mr Sherborne said: "He even sent these terrified women unpixelated images of themselves to show them what would be published in the newspaper if they didn't play ball."
He said Mr Mosley's involvement with the paper had a tragic end when his son committed suicide - something he blamed on the publicity.
"His son, who was suffering from depression, died from an overdose - something he strongly believes was in some way attributable to the very public humiliation he received."
Mr Sherborne added that Mr Mosley was "mobbed" by journalists as he cleared his son's home despite a plea for privacy and one journalist posed as a rambler to secure pictures of the funeral.
The inquiry continues.