By Chris Greenwood
Last updated at 12:01 PM on 5th July 2011
News International boss Rebekah Brooks's position looked increasingly untenable today as both David Cameron and Ed Miliband condemned the hacking of Milly Dowler's phone.
The Prime Minister described the allegations as a 'truly dreadful act', while Labour leader Ed Miliband urged Brooks to 'consider her position' and "examine her conscience'.
Their words were backed by the Dowler family's lawyer Mark Lewis, who said of Brooks's position: 'It is a matter for her own personal conscience to decide.
Close: Prime Minister David Cameron today condemned the hacking of Milly Dowler's phone by News of the World investigators while his friend Rebekah Brooks, right, was editor
David Cameron, speaking from Kabul this morning, said the hacking, if true, is 'a truly dreadful act' 'We have to wait and see whether she decides to do the honourable thing.'
The condemnation from Mr Cameron is a major blow to Ms Brooks, who considers him a personal friend.
Both have homes in his Oxfordshire constituency and Mr Cameron visited her as a guest during the Christmas period last year.
Their friendship is one of a number the Prime Minister holds with senior media industry figures, who live nearby including Elizabeth Murdoch and Jeremy Clarkson.
It has been claimed that her parents Bob and Sally Dowler also had their phones hacked by a private detective in the weeks after the 13-year-old disappeared in 2002.
Speaking at a press conference in Kabul, Mr Cameron said: 'These are really appalling allegations about the telephone of Milly Dowler.
'If they are true this is a truly dreadful act and a truly dreadful situation.'
Mr Cameron said police investigation the allegations should do so without 'fear or favour'.
He added: 'They should pursue this in the most vigorous way that they can to get to the truth of what happened.'
Today the Dowler family's lawyer Mark Lewis said: 'This is cruel. It is evil that people thought this was the right thing to do.'
The alleged hacking took place when Rebekah Brooks, who now runs the British arm of News International, was editor of the News of the World.
She will not resign over the matter, sources at the organisation said.
Labour leader Mr Miliband said: 'I am shocked by the news of the hacking of Milly Dowler's phone. It beggars belief that anyone would undertake such a cruel and immoral act.
'The police inquiry must get to the bottom of who was responsible for this and who was complicit in it.'
He also criticised the News of the World for the 'culture' that allowed it to happen. He said: 'Of course she (Brooks) should consider her position but this goes well beyond one individual.
'This is about the culture and practices, which were obviously going on at that newspaper, the News of the World, over a sustained period of time.
'Cruel': Investigators for the News of the World are accused of hacking Milly Dowler's voicemail. Ed Miliband has attacked the newspaper for its actionsOperation Weeting is mainly focused on the News of the World's activity during 2005 and 2006, by which time Rebekah Brooks had left the paper fro the Sun.
But the Dowler episode, in March 2002, happened while she was editor.
When she took over the paper in 2000, Brooks brought back Greg Miskiw from New York, shortly after he had been sent there as U.S. correspondent.
She made him her assistant editor in charge of news. It was Miskiw who then hired private investigator Glenn Mulcaire, who proceeded to steal confidential data and hack voicemails.
While Brooks was in the editor's chair, the News of the World also regularly hired Steve Whittamore, who ran a network of specialists who stole information from British Telecom, mobile phone companies and the DVLA.
Records published by the Information Commissioner's Office show that 23 journalists from the News of the World hired Whittamore a total of 228 times (including for the purchase of addresses and ex-directory numbers relating to Milly Dowler's disappearance).
Journalists who worked at the News of the World say that their use of private investigators was routine, open and officially sanctioned.
The former showbusiness reporter, Sean Hoare, who worked there under Brooks, last year told the New York Times that he was actively encouraged to hack into voicemail by her deputy, Andy Coulson.
One of Brooks's assistant editors, Paul McMullan, told the Guardian last year that he personally had commissioned several hundred acts that could be regarded as unlawful - which senior editors were of.
'It wasn't about a rogue reporter, it wasn't just one individual, this was a systematic series of things that happened.
'What I want from executives at News International is for them to start taking responsibility for this.'
He added: "They (the public) will be horrified that the grieving parents of an abducted child were made to go through further torture that somehow she was alive because her voicemails were being retrieved or deleted.
'People will ask "where have we got to?" that that was thought to be an acceptable way for parts of the British press to behave.
'My wife said to me this morning "this is sick, what was going on" and I think that is going to be the reaction of people up and down this country.'
Asked if the Prime Minister backed the Labour leader's call, a Downing Street spokesman said: 'We should await the outcome of the police investigation into phone hacking.'
Mr Miliband's words were echoed by shadow Home Secretary Yvette Cooper.
She said: 'Everyone across the country will be deeply disturbed and horrified at this shocking news. The idea that private investigators working for a newspaper would hack into the phone of a missing 13-year-old girl is truly despicable.
'It is deeply distressing that the Dowler family, who have already been through so much, should now have to go through yet another media ordeal.
'I am now seeking immediate assurances that these actions did not affect the police inquiry into Milly Dowler's disappearance.'
Bob and Sally Dowler's solicitor, Mark Lewis, said the 'heinous' actions could have jeopardised the police inquiry as messages were deliberately deleted from Milly's phone to create space for new ones.
This meant her parents clung to 'false hope' that she was still alive because police wrongly thought she was erasing voicemails when, in fact, she was already dead.
At the time she vanished in March 2002, they had been sending desperate text messages and voicemails to her. They now fear those pleas were listened to by the hackers.
Police believe that if Milly's abductor had been accessing the phone at the time of the hunt for her, those deleting the messages may have destroyed potential evidence.
It is alleged the hackers deleted the messages because Milly’s phone - an old model - had a limited memory, meaning no more voicemails could be left.
Controversy: Rebekah Brooks (left) was editor of the News of the World at the time of the allegations while her predecessor Andy Coulson (right) resigned earlier this year as David Cameron's Director of Communications as a result of the phone hacking scandal
Grief-stricken: Bob and Sally Dowler with daughter Gemma, centre, speaking outside court after Bellfield's convictionMr Lewis said her parents had already been through 'so much grief and trauma' before these 'further distressing revelations'.
Last month they revealed how traumatised they had been by the trial that led to the conviction of Levi Bellfield, 43, for Milly's murder.
Mr and Mrs Dowler said they were in effect put on trial as their personal lives were torn apart in the witness box.
'It is distress heaped upon tragedy to learn the News of the World had no humanity at such a terrible time,' said Mr Lewis.
'The fact that they were prepared to act in such a heinous way that could have jeopardised the police investigation and give them false hope is despicable.'
The Dowler family were only told about the hacking in April - more than nine years after their daughter went missing.
Her remains were found 25 miles away from her home in Walton-on-Thames, Surrey, in September 2002.
Abuse: Bellfield is seen here with his former girlfriend Johanna Collings at Yateley Heath - where Milly's body was found years later
Grief: Flowers are laid for schoolgirl Milly Dowler outside Heathside School, Weybridge, in September 2002 after her body was found
Grieving: Parents of Milly Dowler, Bob and Sally, make an appeal during the time of her disappearance in 2002A source close to the inquiry said officers were 'shell shocked' when they learnt about the hacking. 'This is devastating news for the family,' he said.
'When the trial finished they wanted to reclaim the memory of Milly for themselves. But this has thrown it open again.'
Police sources said they did not know what journalists hoped to achieve by the alleged hacking of Milly's phone. But it is possible they were after fresh leads in the search for her.
It also emerged yesterday that Colin Stagg, the man cleared of murdering Rachel Nickell, may have been hacked as early as 2000.
The latest revelations are likely to mark a turning point in Operation Weeting, Scotland Yard's investigation into hacking at the News of the World, in which five people have been arrested.
Detectives found evidence of the Dowler hacking amid paperwork seized from the home of private investigator Glenn Mulcaire, who was jailed in January 2007, along with former News of the World royal editor Clive Goodman, for intercepting voicemail messages.
Scotland Yard was first alerted to phone hacking in 2005 when royal aides reported their suspicions to police.
After the conviction of Goodman and Mulcaire, concerns were raised that the initial inquiry was too limited.
In January Scotland Yard announced a new inquiry after detectives were handed 'significant new information' by News International.
News International has reportedly set aside a multi-million pound fund to settle compensation claims with victims. They include actress Sienna Miller, who was recently paid ?100,000, and sports pundit Andy Gray, who received ?20,000.
A spokesman for News International said: 'We have been co-operating fully with Operation Weeting since our voluntary disclosure in January restarted the investigation into illegal voicemail interception.
'This particular case is clearly a development of great concern and we will be conducting our own inquiries as a result. We will obviously co-operate fully with any police request on this should we be asked.'
Killer: Levi Bellfield, pictured in 2011 (left) and 2004 (right) was convicted of murdering Milly Dowler