The parents of a murdered British schoolgirl have pleaded for the country's newspapers to curb phone hacking and covert photography practices as a public inquiry into UK media standards turned the spotlight on the celebrity obsessed press.

The disclosure in July that a long-simmering dispute over phone hacking at Rupert Murdoch's News of the World tabloid had spread from celebrities to a murder victim provoked an national outcry that led to the closure of the newspaper.

Within days, his News Corp group withdrew its bid to buy the 61 per cent of broadcaster BSkyB it did not already own; its British newspaper arm News International shut the 168-year-old paper and Prime Minister David Cameron ordered the inquiry.

To a silent court room on Monday, Sally Dowler told how she had suddenly become excited during the hunt for her daughter when she realised that phone messages left on Milly's phone were being deleted. This led her to believe, falsely, Milly was still alive.

Bob Dowler said the family had felt hounded and afraid to leave their home, with journalists popping up from behind hedges to fire questions, and photographers taking pictures during intensely private moments.

"It felt like such an intrusion into a really private grief moment," Sally Dowler told the central London court room.

The Dowlers, who have become key figures in the national debate about media practices, were appearing as the first witnesses in the inquiry as Hollywood stars and other high-profile figures unite to expose questionable media tactics.

Shocking revelation

Another witness, columnist Joan Smith, said: "We do have a tabloid culture that is almost infantile in its attitude to sex and private life."

Actor Hugh Grant, who also spoke to the inquiry on Monday, said he believes his phone was hacked by British tabloid The Mail on Sunday. It was the first time Grant has implicated a newspaper not owned by Rupert Murdoch in the wrongdoing.

Grant said a 2007 story about his romantic life could only have been obtained through eavesdropping on his voice mails.

Graham Shear, a lawyer who has acted for famous footballers and entertainers, told the inquiry that the tabloid press had in recent years lost their ethical compass and become "almost untouchable" in their approach to dealing with the public.

Most of the focus of the inquiry so far has fallen on News International, whose lawyer has admitted that phone-hacking was widespread until 2007, when one reporter was jailed, and possibly beyond.

The inquiry, headed by senior judge Brian Leveson and due to last a year, will make recommendations that could have a lasting impact on the industry, lead to tighter media rules or at least an overhaul of the current system of self-regulation.