Scotland Yard detectives have arrived in Portugal to begin the excavation of a number of sites as part of the probe into the disappearance of Madeleine McCann.
Specialist officers are expected to examine several sites in Praia da Luz after permission to dig was granted by Portuguese authorities.
Madeleine went missing from the area while on a family holiday on May 3, 2007, when she was aged just three.
The excavations, which are expected to be conducted by forensic experts, are not thought to necessarily be in connection with a search for the youngster's body or remains.
Janice Runacres, a former forensic manager with the Metropolitan Police, told Sky News: "They will be looking at aerial photography, maybe taking aerial photography now, and looking at historic aerial photography to see if there is any changes in the landscape, changes in perhaps more lush vegetation in certain areas, and this may indicate areas for further focus."
The request to search a number of sites is thought to be among a series of requests made by British detectives in connection with the search for Madeleine.
At the weekend Madeleine's parents, Kate and Gerry McCann, thanked the public for their support at a prayer service on the seventh anniversary of her disappearance.
The couple were joined by about 100 well-wishers, friends and relatives for a low-key open-air service in the centre of Rothley, Leicestershire, which saw candles being lit for all children around the world who have been taken away from their parents against their will.
They also spoke of the family's gratitude that the Metropolitan Police investigation was now moving on to a "very active" phase.
It comes amid the news British police have reportedly been refused permission to search the homes of three burglary suspects.
Sky Crime Correspondent Martin Brunt, in Praia da Luz, said: "One of the local newspapers, the News Journal, is reporting that one of the things that is being rejected by Portuguese authorities is a Scotland Yard plea to search the homes of three men who used to work here at the Ocean Complex at the time Madeleine vanished and are suspected of a number of break-ins in the days, weeks leading up to her disappearance.
"So that's a blow for Scotland Yard. They had identified three ex-workers who they wanted to talk to, potential suspects not necessarily around Madeleine's disappearance, but had been involved in break-ins, according to information Scotland Yard had."