The family of murdered schoolgirl Milly Dowler are to press for "stronger, clearer and faster action" from the Government over phone hacking in meetings this week with senior politicians.
Milly's parents Bob and Sally Dowler are suing the News of the World over claims their daughter's phone was targeted by the newspaper when she went missing in 2002.
Her mother and sister Gemma will be among victims and campaigners meeting Deputy Prime Minister Nick Clegg on Monday in an effort to secure a sufficiently comprehensive inquiry.
Talks will be held later in the week with Prime Minister David Cameron, Downing Street said, after being forced to withdraw an earlier announcement that the premier would be involved.
And the Media Standards Trust, which has led a major campaign on the issue and has organised the meetings, said it was also arranging a session with Labour leader Ed Miliband.
News that Milly's phone was among those targeted kicked off a wave of public outrage, fuelled by reports that terror victims' families also had their messages hacked, which resulted in the Sunday newspaper's closure and the announcement by Mr Cameron of a judge-led inquiry into the scandal.
After details of the meeting with Mr Clegg emerged on Saturday night, Downing Street said it had been contacted by the charity and that Mr Cameron would also hold talks with the group - but that had not been confirmed by the Trust.
In a fresh statement on Sunday morning, a Number 10 spokesman said: "At the request of Milly Dowler's family the meeting with the PM will take place later in the week."
It is thought the Trust, which led the Hacked Off campaign for a public inquiry, is keen to be able to address its concerns separately with the three main party leaders.
Among others attending are former Scotland Yard deputy assistant commissioner Brian Paddick, phone hacking victim Nicola Phillips and solicitor Mark Lewis - who represents the Dowlers and other hacking victims. Actor Hugh Grant, however, who had been reported to be part of the delegation, will not be attending, the Trust said.