Esti's mother broke up with her father three years ago

Police searching for a father who has taken his four-year-old daughter abroad during a custody battle have new evidence that he plans to stay overseas.

An international hunt involving Interpol is under way to find Simon Clayton, 41, a Hay-on-Wye book dealer, who disappeared with his daughter, Estelle or Esti, on 11 April during an access visit.

It is feared he may have fled to Morocco.

On Wednesday, it emerged that Dyfed-Powys Police had found a witness who spoke to Mr Clayton before he left and who claims the father said he would not be returning home.

That information contradicts a note Mr Clayton left at his house saying that he was taking his daughter on a holiday for three weeks and had booked a place on a ferry that left Portsmouth for Caen in France.

In an emotional appeal on Monday, Esti's mother 29-year-old Polish-born Anera Clayton, said: "He is a very loving and caring dad, but he is a little bit obsessed with his little daughter."

Simon Clayton left a note he would be back in three weeks

"Esti is a very happy, pretty girl - full of life and energy," she added.

"I am missing her terribly and I am sure that she is missing me and her friends."

Detective Inspector Steve Hughson, who is based at Brecon and is leading the inquiry, said he now believed Mr Clayton was likely to be away from home for a longer period of time.

"It makes it more serious from our point of view," he said.

Detectives are working with their French counterparts but Mr Hughson said there is no specific information that the pair are on the Continent.

He added: "Everybody says he loves his girl, however our concerns are rising by the day."

Previous possible sightings of the pair include one in Spain and another in Germany.

Officers believe it is possible the father and daughter were headed for Spain or Morocco, where they had been on holiday last year.

Aneta Clayton broke down several times at the police press conference

Recently divorced, the Claytons separated three years ago. They married in 1997 after meeting in Poland where Mr Clayton had travelled on business.

The custody of their daughter is still being decided by the courts and a hearing was due soon.

Police have appealed to holidaymakers - either leaving or returning from Europe - for any information about sightings of the pair.

Mr Clayton is believed to be travelling in a red Volkswagen Caravelle, registration number A276 OFJ.