Sally Dowler, who was giving evidence alongside her husband, Bob in the Leveson Inquiry, which is exploring the ethics of the media, described the moment she gained access to Milly’s voicemail.

She said: “I rang her phone and it clicked through on to her voicemail and I just jumped and said: ‘She’s picked up her voicemails

Bob, she’s alive’. When we heard about the hacking that was the first thing I thought,” she said.

“I told my friends, ‘she’s picked up her voicemail, she’s picked up her voicemail’.”

Prime minister David Cameron called for the Leveson Inquiry in July after it emerged the News of the World had commissioned private detective Glenn Mulcaire to hack Milly Dowler’s phone after she disappeared in 2002.

Milly’s father, who described Mulcaire’s actions as “despicable” told the inquiry on Monday the gravity of Mulcaire’s actions, which included deleting the messages left for Milly, from her phone, warranted an investigation.

“I think there is a much bigger picture, obviously, but I think that given that we learned about those hacking revelations just before the trial for the murder of our daughter, it was extremely important that we understood and people understand exactly what went on in terms of these practices, to uncover this information from the hacking situation.”

The inquiry heard Mulcaire, who was employed by the now-defunct News of the World, hacked Milly Dowler’s phone and, in doing so, induced “euphoria” in her family as it gave them hope their missing 13-year-old daughter was alive.

The inquiry heard today how Sally Dowler rang her daughter’s phone repeatedly in the weeks after she vanished as she walked home in Walton-on-Thames, Surrey, in March 2002.

Milly’s mother also revealed she did not sleep for three nights after being told her daughter’s phone had been hacked.
“As soon as I was told it was about phone hacking, literally I didn’t sleep for about three nights because you replay everything in your mind and just think, “oh, that makes sense now, that makes sense”.’

Surrey police has been ordered to release documentation, which could implicate officers in the selling of information to journalists about the case.

The accusations come after photographers snapped private pictures of the Dowler family retracing Milly’s final movements – an event known only to immediate relatives and the police.