A mystery phone call from a man claiming to know the whereabouts of missing Madeleine McCann could provide a new lead in the case, it emerged today.
The caller provided such detail that Kate and Gerry McCann put their European search for their daughter on hold in case they needed to act.
However Spanish police have denied reports of the call.
"All I can say is that it is a lie," a National Police spokesman told The Associated Press. "I don't know where this came from but the police have no record of this call anywhere." Scroll down for more ...
A 'credible' caller claiming to know where Madeleine is gave enough detail for the McCanns to put a brief hold on their trip to AmsterdamThe official spoke on condition of anonymity under police ground rules.
The couple reportedly were informed of the potential development while in Germany, where they were appealing for information about their four-year-old child
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It is 35 days since Madeleine was abducted from her bed in the Algarve resort of Praia da Luz.
The "credible" call was taken from a man who wanted to speak directly to the McCanns, according to a Spanish police source.
It was traced to an unregistered pay-as-you-go phone from an unidentified country but not thought to be Morocco, where a previous possible sighting of Madeleine was reported.
The caller did not reveal his identity or nationality, but the information was considered important enough to alert Mr and Mrs McCann, the source said.
At around 3pm yesterday, the couple - who were about to go to Tempelhof airport in Berlin to fly on to the Netherlands - were advised that the caller might try to contact them, so they stayed on at the British embassy.
At 6pm, journalists travelling in the eight-seater private jet with the McCanns were told by the flight crew that there might be a change in destination.
They revealed they had been asked to draw up a new flight plan involving a possible change from Amsterdam to East Midlands Airport.
It was thought the McCanns might need to go back to the UK to talk to advisers about the call. But all efforts to re-establish contact with the man failed and the couple decided to go on to Amsterdam.
They left Berlin at 7.30pm, three hours later than planned, for the hour-long flight to Schiphol Airport in Amsterdam to continue their search.
Kate and Gerry McCann looked exhausted today as they prepared for the trip to Amsterdam and recovered from their shock at being asked if they had anything to do with Madeleine's abductionMr and Mrs McCann are thought to be on standby, ready to return to the UK if necessary. A Spanish police source said: "A man called saying he knew where Madeleine was and wanted to speak to the McCanns.
"This did not appear to be a crank call and the information was felt credible enough to warrant the couple being informed immediately.
The McCanns were in Berlin preparing to fly to Amsterdam but were advised to delay take-off.
The situation was so critical that it was felt they could not afford to be out of touch on the plane, even for an hour during the short flight.
Kate and Gerry McCann looked utterly exhausted as they prepared for their trip to Amsterdam.
The trip, part of the the battle to find their missing daughter, has a personal note - they lived there when Madeleine was a baby.
The couple spent all of 2004 in the Dutch city and have not returned since. They said they never dreamed they would be back today without Madeleine.
It is 35 days since the four-year-old was abducted from the Algarve resort of Praia da Luz. Her parents have flown across Europe from Portugal to Italy, Spain, Germany and now the Netherlands to raise awareness about her disappearance.
Today's visit and appeal for information marks the end of the European aspect of their campaign to find Madeleine.
A further trip to Morocco and northern Africa is planned for the weekend.
Mr and Mrs McCann flew from Berlin to Amsterdam by private Hawker jet last night and spent a quiet but emotional evening with friends.
Mr McCann, a cardiologist, worked in Amsterdam three years ago, focusing on MRI imaging of the heart.
Madeleine was a little more than eight months old when the couple arrived and Mrs McCann was pregnant with twins Sean and Amelie when they left.
The couple said they expected today's visit to be a highly emotional one.
They will undertake the now familiar round of interviews and media appeals to help track down their daughter.
Portugal is a popular destination for Dutch tourists and the McCanns hope their public appeal will encourage someone with information to come forward. Scroll down for more ...
Four-year-old Madeleine has been missing since May 3They are due to meet British ambassador Lyn Parker and the Consul General in Amsterdam Bernhard Garside.
They will then discuss child welfare issues with Fronske Eendebak Winkel, national police co-ordinator for missing persons and representatives from the organisation Child Focus.
Mr and Mrs McCann are keen to return to the Algarve promptly this afternoon after two nights away from two-year-old Sean and Amelie.
They also want to get back in time to attend a jazz concert in honour of Madeleine being held in Lagos at 8.30pm tonight.
Yesterday, the campaign to find their daughter was briefly overshadowed when the McCanns were forced to deny they had any involvement in her abduction.
They looked appalled when they were asked by a German journalist if they had anything to do with Madeleine's disappearance.
Sabine Mueller from German Radio said there were people suggesting that the couple's behaviour since her abduction was not normal.
"They seem to imply that you might have something to do with it," she said.
Mr McCann hit back, saying: "I have never heard before that anyone considers us suspects in this and the Portuguese police certainly don't. "Without going into too much detail, we were with a large group of people. There is absolutely no way Kate and I are involved in this abduction." I know where Madeleine is, says mystery man | the Daily Mail
