Police believe it is now likely Ben Needham, who disappeared 25 years ago, was likely killed in an accident.

British toddler Ben Needham vanished while holidaying with relatives on the Greek island of Kos on July 4, 1991.

The 21-month-old was in the care of his grandparents, who had moved to Greece, when he disappeared while playing outside their farmhouse.

The toddler’s disappearance remained one of the UK’s biggest child disappearance mysteries.

However Detective Inspector Jon Cousins said he now believed Ben was dead, The Sun reported.

Ben Needham was 21 months old when he vanished near a farmhouse where his family was staying on the Greek island of Kos in July 1991.Source:AFP

Insp Cousins also said a significant item, believed to have been in Ben’s possession at the time of his disappearance, had been found during the search on the Greek island.

At a press conference Supt Cousins said: “Based on the information that I have now as a result of an extensive and thorough investigation it’s without doubt that the current line of inquiry is the most probable cause for Ben’s disappearance.

“My team and I know that machinery including a large digger was used to clear an area of land on July 24, 1991 behind the farmhouse that was being renovated by the Needhams.

“It is my professional belief that Ben Needham died as a result of an accident near to the farmhouse.”

Detective Inspector Jon Cousins speaks with a team member as they walk past rubble at the new second search site approximately 1km from the farmhouse where Ben went missing. Picture: Chris McGrath/Getty ImagesSource:Getty Images

Police launched the three week search after a witness said the toddler was killed by a mechanical digger driven by Konstantinos “Dino” Barkas, who has since died of cancer.

The witness told Greek police that his longtime friend accidentally crushed the boy to death with the digger after he wandered onto the site.

His workmates helped keep his dark secret ever since, out of loyalty to their friend.

The man who came forward after an appeal for new information was aired on Greek TV earlier this year.

Ben’s disappearance sparked numerous sightings and theories as to his fate.

Speaking to the Daily Mirrorafter the search ended Ben’s mother Kerry Needham said further reports had corroborated the theory.

She added: “One man has taken a secret to his grave. Police believe that.

Insp Jon Cousins displays pieces of ancient artefacts found during the excavation of soil deposits at the second search site. Picture: Chris McGrath/Getty ImagesSource:Getty Images

“They know enough ­information to know that happened. Someone else has come forward who was a teenager working for Dino.

“He learnt about Ben and asked Dino a few times and he kept saying, ‘No not possible’ but then in 2012 this person asked Dino about it again and he admitted to him in 2012: ‘I don’t know for sure but yes it’s possible’.”

At the outset police said they were “optimistic” a new excavation would provide answers.

Ben’s mother has been told to prepare for the worst.

She told Good Morning Britain last week: “We need those answers whether they are good or bad.

Forensic specialists and an archaeologist have been searching an olive grove next to the farmhouse where Ben was last seen playing. Picture: Chris McGrath/Getty ImagesSource:Getty Images

“Unfortunately, it looks like we are going to get a bad one.”

When asked if that answer would give her a sense of closure, she said: “In a way yes because then we’ll know.

“You know 25 years living and not knowing where your child is, is torment.

“I don’t like to say it but then at least we would know and it would be closure and he can be laid to rest and we can remember him as he was.”

This article has been republished with permission from The Sun.

— with staff writers