As the hunt for three-year-old Madeleine McCann continues in the Algarve, the mother of toddler Ben Needham who disappeared in July 1991 tells the BBC she understands how the girl's parents are feeling.

Kerry Grist's son Ben, from Sheffield, vanished from outside a farmhouse on the Greek island of Kos nearly 16 years ago, when he was just 21 months old.

She says watching television footage of Mrs McCann in Portugal has brought back memories of that day.

"It was like a mirror image, the look on her face, the fear, the worry, everything," she said. "It was like seeing myself 15 years ago."

She said Madeleine's mother would be finding life after her daughter's apparent abduction "very, very difficult".

"She is going to have a lot of different emotions. She is going to be really frightened of not knowing what has really happened to Madeleine - very confused and just feeling like her heart has been ripped out.

"The only thing I can try and advise her on is to stay strong, stay in control of everything - the police investigation, the media side of it - just stay focused and stay strong."

The way to get through each day was to "get as much love and support" from family and friends as possible, she said.

Abduction theories

Mrs Grist, who has remarried since her son's disappearance, believes the frustrations of working with a foreign police force, such as dealing with language barriers and different legal processes, adds to the distress.

"It is really, really difficult to put all your trust and faith into somebody that is foreign - that doesn't understand our culture, doesn't understand our ways," she said.

Mrs Grist's son Ben, who would be 17 now, has not been seen since his disappearance from the house her parents and brother were renovating, despite appeals by his family and the British authorities over the years.

Theories have included that Ben was killed, abducted or sold on to a family who could not have a child, but police have never closed the file.

Mrs Grist said that in the beginning it did not enter their heads that Ben might have been abducted.

"You live every day just thinking someone is going to walk back through the door with him," she said.

But his family have never given up hope of finding him. They believe he was "taken to order", passing through the hands of child smuggling gangs and could be "anywhere in the world".

"There is no evidence at all in the past nearly 16 years to say that Ben is dead," Mrs Grist said.

"There was never anything at the time, no traces were found, no clues were found to insinuate that.

"And in my heart I feel that if I thought for even one minute that Ben was no longer alive, I would have given up by now - and I can't.

"There is something that drives me on to keep looking, keep looking and keep fighting for him."