A team of British police officers has arrived on the Greek island of Kos to examine a mound of earth and rubble close to where toddler Ben Needham went missing 21 years ago.
The officers are leading a group of specialist search advisers who will be supporting the Greek authorities as they decide whether to excavate the mound, South Yorkshire Police said.
Ben, from Sheffield, vanished on the island in July 1991, when he was 21 months old, after his mother and grandparents moved there from Sheffield.
Despite a number of possible sightings and a range of theories about what happened to him, no trace of the youngster has been found.
His mother, Kerry Needham, has spent two decades looking for her son and has consistently said she believes he was abducted and is still alive.
Today, a South Yorkshire Police spokeswoman said: "South Yorkshire Police is leading a team of specialist search advisers who have travelled to the Greek island of Kos to support the Greek authorities as they search for missing Sheffield toddler Ben Needham.
"Greek police are pursuing a line of inquiry centred on the grounds of the property from which Ben disappeared in 1991 aged 21 months.
"Beginning tomorrow, work will begin to examine the ground, including using geophysical ground examination equipment, to determine whether any area should be dug."
The spokeswoman said other specialist resources had been deployed including a forensic archaeologist and search dogs. She said the operation is expected to last a week to 10 days and follows a Greek police request for specialist support.
"During the past 18 months, South Yorkshire Police has also reviewed all material held by the Greek police in relation to Ben's disappearance in order to support the Greek inquiry.
"South Yorkshire Police (SYP) has also obtained Ben's DNA from Sheffield Children's Hospital.
"SYP has for a number of years supported Ben's mum Kerry and other members of the family."
Mrs Needham, 41, told the Daily Mirror: "This is an elimination process and that's how I'm dealing with it.
"It's one of the most important things to happen in 21 years."
The new search is centred on a large mound which is now grassed over.
It is near a farmhouse next to the one Ben's grandparents were renovating in 1991.
One theory is that it is building material which was dumped at the time the toddler went missing and the youngster could have been accidentally buried beneath it.
But Mrs Needham has said in previous interviews she believes the large mound was already there when Ben disappeared.
Earlier this year, she said: "I find it very, very unlikely that Ben is there, unless he buried himself."
Today MP Angela Smith, who has supported Mrs Needham and her family, said she believed the search was important as it ruled out another line of inquiry.
Mrs Smith, who is Labour MP for Penistone and Stocksbridge, told BBC Radio Sheffield: "Hopefully they won't find Ben in that rubble and it closes down another line of inquiry and narrows down the possibilities."
She said: "I know that she (Mrs Needham) will be very keen for this work to be undertaken and rock solid confident, I'm sure, that they won't find Ben there."