Ben Needham vanished on the island of Kos 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.
The Daily Mirror said a team of British search experts is to begin digging up a mound of earth in a bid to find out if he may have been buried there.
His mother, Kerry Needham, 41, told the paper: ''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.'
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She has previously said she believed the mound of rubble, near the family's farmhouse, was already there when Ben went missing.
The team of specialist search experts drawn from police forces across the UK is to begin searching tomorrow, the paper said.
Earlier this year Ms Needham dismissed reports that Benmay have died in a building site accident and been buried under rubble near his family's farmhouse on Kos.
Ben's disappearance sparked an international hunt, with the Greek police alone logging up to 200 possible sightings of the missing boy.
In the months and years after he disappeared, the most common theory was that he had been snatched by gypsies.
It has also been suggested that Ben, who would now be 22, was taken for adoption by a non-Greek family, perhaps in Scandinavia, Australia or the United States.