20 October 2012 Last updated at 09:01 ET

Ben Needham: Grandfather joins Kos search

Ben's grandfather was asked to show officers how the area had changed since 1991

The grandfather of a child, who went missing on a Greek island 21 years ago, has joined a new police search.

Officers are searching land on Kos for the remains of Ben Needham, from Sheffield, who was 21 months old when he vanished in 1991.

Eddie Needham and his wife were looking after Ben on the day he disappeared.

British police forces helping Greek authorities search near the family's former farmhouse said so far no significant discoveries had been made.

Specialist search dogs and diggers are searching a pile of rubble where the little boy was last seen.

At the scene

Danny Savage North of England Correspondent, BBC News

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It may be out of season here in Kos but the sun is still hot and the specialist officers excavating the ground in a bid to find any trace of Ben Needham will find the work hard going. They are here because South Yorkshire police pledged to do all they could to help Kerry Needham - Ben Needham's mother. No trace of him has ever been found. After Madeleine McCann, Ben Needham is the most infamous case of a British child disappearing abroad. Speculation has been rife that he may have been abducted and the campaign to find him has even produced artists' impressions of what he would look like now in a bid to trace the young man who would have turned 23 this month. The Greek authorities, and many local people in Kos, have always doubted the abduction theory. A tragic accident is what many here think happened.

The now overgrown mound is next to the farmhouse which Ben's grandparents were renovating at the time.

Eddie Needham, 63, was asked to show officers how the area had changed over the years.

Det Sup Matt Fenwick, of South Yorkshire Police, who is leading the British team, said: "He [Mr Needham] really is emotional about this. It is difficult for him to come back to the scene.

"He is not comfortable with it but he knows it is something he has to do."

Ben was playing outside the property when he disappeared.

One theory is that the toddler could have been accidentally buried beneath building material which had been dumped at the time.

Despite a number of possible sightings, no trace of the boy has been found.

Previous theories on Ben's disappearance have included murder or abduction.

Ben's mother, Kerry Needham, has always said that she believes her son is still alive but has supported the new search.

Mrs Needham, supported by a police family liaison officer, will also travel to Kos during the search.

The search is expected to last for 10 days.