Kate and Gerry McCann are to ask a High Court judge to order the release of police documents which they hope will kick-start the search for their missing daughter Madeleine, The Daily Telegraph can disclose.

Kate and Gerry McCann are determined to everything necessary to search for their daughter

The McCanns hope their application to Mrs Justice Hogg will result in Leicestershire Police opening their files on scores of reported sightings of Madeleine, most of which have been passed on to them by police in Portugal, where the
four-year-old disappeared in May last year.

Until now police in Leicestershire, the McCanns' home county, have refused the couple's requests for information about sightings, saying they are bound by the terms of an agreement with Portuguese police.

But Mr and Mrs McCann, who retain the services of a Spanish-based detective agency, are anxious to make sure that every possible lead has been checked out, which they believe the Portuguese police, whose investigation is gradually being wound down, may not be able to do.

The Telegraph can also disclose that Madeleine was made a ward of court last summer at the request of the McCanns, to empower judges to act in her best interests in any legal dispute such as the case which is about to be heard.

Clarence Mitchell, the McCanns’ spokesman, said: “I can state that on the instigation of Gerry and Kate McCann Madeleine is a ward of the High Court of England and Wales.

“An application has been made on Madeleine’s behalf by her parents for disclosure of certain documents. The hearing is currently scheduled for July 7 in the High Court in London.

“It has been the stated intention of Gerry and Kate McCann to leave no stone unturned in doing everything necessary to search for their daughter, as would any parent.

“This application is just part of their search for Madeleine.”

Madeleine’s status as a ward of court has never been disclosed by her parents, who quietly made a wardship application in the High Court just weeks after she went missing.

The couple’s legal team had advised them to ask for Madeleine to be made a ward of court because wardship status gives the courts certain statutory powers to act on her behalf in legal disputes such as the one which has arisen with Leicestershire police.

They still believe their daughter is alive and hope the police files may contain information which could yet lead to a breakthrough.

The case is listed to be heard in open court on July 7 in the Family Division of the High Court in London, and is expected to be contested by Leicestershire Police, according to legal sources.

Clarence Mitchell, the McCanns' spokesman, said: "Kate and Gerry have always said that they will do whatever is necessary to find Madeleine and that they will leave no stone unturned in their search for their daughter.

"They will take whatever legal steps are necessary if there is information out there that can assist their private investigation into finding Madeleine. Beyond that I cannot make any comment."

Mr Mitchell said the hearing would not involve any attempt by the McCanns to clear their names by proving they were not involved in their daughter's disappearance from a holiday apartment in Praia da Luz. They remain official suspects, or arguidos, in Portugal.

In recent months the couple have become increasingly frustrated at the slow progress of the Portuguese investigation, and they suspect that many possible sightings of Madeleine have not been followed up at all.

If they are given access to the police files on reported sightings, each one will be looked into by private investigators retained by the couple.

For the past year the McCanns have employed Metodo 3, a Barcelona-based detective agency, to carry out an investigation in parallel with the Portuguese police inquiry.

The agency has checked out sightings as far afield as North Africa and South America – all of which have proved to be false – using either its own staff or affiliated firms, which it says it can do far more quickly than the police.

In one instance earlier this year, the agency ruled out a sighting of Madeleine in Chile within three hours of receiving a tip-off, by employing local investigators to track down the girl concerned. The agency argues that police would have taken days to achieve a similar result because they would have been hampered by bureaucracy and official procedure.

Earlier this week Portugal's Attorney General suggested that police files may be opened up at the end of July, but the McCanns fear his comments may prove to be another false dawn.

Their case is being heard in the Family Division because it involves the welfare of a child. Mrs Justice Hogg, a specialist in child welfare cases, is the sister of former cabinet minister Douglas Hogg and the daughter of former Lord Chancellor Lord Hailsham.