The father of a disabled girl who has been missing with her mother for three days urged them to come forward in a national television appeal.
Neil Whitehead told BBC's Missing Live programme he believed Millie, nine, may have been taken to remote countryside.
His former partner Jude Richmond and Millie were last seen at home in South Cerney, Gloucestershire, on Sunday.
Mr Whitehead said he was concerned Millie, who has cerebral palsy, did not have her walking aids.
Police said they believed Mrs Richmond, who runs runs a floristry business with clients who include royalty and celebrities, was vulnerable and possibly depressed.
Mr Whitehead, who contacted the programme to make the plea, described Millie as "very engaging" and said she had a fantastic relationship with her mother.
He said: "We had various emails from Jude saying that she wanted to take Millie away to somewhere secluded, in a very natural environment, away from metal with log cabins.
"The thing that is worrying is that her walking aids, her wheelchair and her electric car were left.
"Jude seems to have disappeared leaving everything open in the house."
Mr Whitehead had said he understood Mrs Richmond was having issues with her marriage, but when he spoke to her the day before she went missing, she was "calm and sensible".
Jude Richmond and daughter Millie have been missing since Sunday
Divers from Avon and Somerset Police have begun a search of the lake, directly behind Mrs Richmond's home in Gloucestershire.
Officers were alerted to the pair's disappearance by the family cleaner at 1000 GMT on Monday.
The initial search concentrated on the house and immediate area and involved officers, a police dog and helicopter.
Appeals for information have led to about 25 calls from people offering information and help with the search.
Mrs Richmond and Millie were also seen with what police said was a "mystery man" on Sunday.
He was described as white, in his 40s, approximately 6ft tall, of large build with broad shoulders and dark blond hair.
Mrs Richmond is about 5ft 11in, of slim build, with blonde, shoulder length hair.
She was last seen wearing a grey, long sleeved T-shirt, jeans and boots.
Millie is described as being thin and pale, with shoulder-length blonde hair.
BBC News, 18th March 2009