This article was first published on guardian.co.uk on Thursday September 13 2007. It was last updated at 15:51 on September 13 2007

Gerry and Kate McCann: have been speaking regularly to former News of the World editor Phil Hall. Photograph: Armando Franca/AP

Kate and Gerry McCann, the parents of the missing four-year-old Madeleine McCann, are looking for a new full-time public relations adviser after their current PR, Justine McGuinness, decided to step down.

Ms McGuinness has told journalists she is planning to cease acting as the McCann's PR on Saturday, September 15.

However, she is believed to have assured the McCanns that she will stay in place if a replacement cannot be found.

A spokeswoman for the McCanns' solicitors, Kingsley Napley, confirmed that Ms McGuinness was stepping down from her role as the couple's PR.

One reason Ms McGuinness has given to journalists for her departure is that the McCanns have been ordered to remain silent because of the changing nature of the investigation and she feels she cannot help them further.

Another is Ms McGuinness's workload - she has been "working 18 hours days for a number of weeks now" according to a source familiar with the situation.

The couple are thought to be looking for a "big hitter", according to one source familiar with the situation, to work as their full-time PR representative as the investigation into their daughter's disappearance enters a new phase.

Ms McGuinness, a 37-year-old former Liberal Democrat parliamentary candidate, was selected through a headhunter to oversee the PR campaign to aid the search for the couple's daughter.

But it is now thought that the McCanns are looking for a different kind of PR advice after they became suspects in the inquiry into their daughter's disappearance and media coverage has become more negative.

The couple are understood to be consulting a number of senior industry figures about their media strategy, with the leading candidate thought to be former News of the World and Hello! editor Phil Hall.

Mr Hall today admitted to MediaGuardian.co.uk that he had been "speaking regularly" to the couple since their daughter disappeared on May 3 in the Algarve in Portugal.

The newspaperman turned PR executive said: "I have spoken to them a number of times and offered advice and [help] assessing the situation and what they are doing going forward and whether they need someone full time or part time."

Asked if he was being lined up to be their full time PR representative, Mr Hall said: "We are discussing the way forward. I have not been hired ... and I gather they are talking to other people."

Asked if he was being paid by the McCanns for his advice he insisted that he was not, adding: "What, when they call up, do I ask them, 'how much?' Of course not. They are very nice people."

Before Ms McGuinness's arrival in Portugal, the McCanns' media relations were handled by a team from the British government led by Sheree Dodd, a former tabloid journalist.

Then Clarence Mitchell, an ex-BBC news presenter, became the voice of the McCanns before Ms McGuinness took over.

Friends and family have also been quoted in newspapers, including Mr McCann's sister Philomela, who is quoted in today's Sun newspaper describing moves by the Portuguese authorities to examine Kate McCann's private diary as "just another way to stick the knife in".

If Mr Hall or a figure like him is hired, it will mark a new phase of the couple's campaign to prove their innocence.

It will also be the second of two high-profile so-called PR "fire-fighting" signings for Mr Hall.

He was taken on by Sir Paul McCartney's estranged wife Heather when newspaper interest in her separation from the former Beatle reached fever pitch in the summer of 2006 and she was targeted for a number of negative stories.

Mr Hall moved into PR in 2005 when he quit his job as Trinity Mirror's editorial director, after losing out to Richard Wallace in the race for the Daily Mirror editor's chair.

He joined Trinity Mirror in 2003 from the Press Association, where he headed the news agency's contract publishing arm.

He quit his job at PA in January 2003 to join Trinity Mirror as the editorial director.

Mr Hall edited the News of the World for five years before leaving in 2000 to make way for Rebekah Wade. He became the editor of Hello! in January 2001 and helped land a number of scoops, including the rights to Victoria Beckham's official autobiography, Learning to Fly.

The McCanns' legal firm, Kingsley Napley, declined to comment on Mr Hall's professional involvement with its clients.