The father of missing backpacker Eddie Gibson is to return to the Far East in search of his son.

Mike Gibson, 59, said he remained determined to find out what happened to the 21-year-old Hove student who disappeared without trace in Cambodia two years ago.

He made the pledge as Sussex Police confirmed there had been no major breakthrough in the case, despite four officers spending ten days in the Cambodian capital Phnom Penh working alongside local detectives.

At a news conference yesterday, at John Street Police Station, Brighton, Detective Chief Inspector Graham Pratt said that while the trip had been useful in firming up Mr Gibson's last known movements his whereabouts remained unknown.

Mr Pratt, who flew to Cambodia with colleagues from Sussex Police's major crime branch, said they had interviewed some of the people Eddie was in contact with while in Cambodia. He also visited some of the hotels and other establishments where he had stayed. They had followed the trail from Phnom Penh to Poipet, a border town with Thailand.

He said: "During our time we interviewed a number of key associates and witnesses. We were able to add some facts to what was already known from the Cambodian investigation.

"Unfortunately, it still remains the fact that Eddie's whereabouts after October 24, 2004, remain a mystery. We have come back with further inquiries that we need to work on and indeed we will be making further suggestions on what work they should do in Cambodia."

Mr Gibson was three weeks into a course at Leeds University when he decided to leave and travel around Cambodia.

Two weeks after his arrival he sent his mother an email saying he was looking forward to coming home. That was the last his family heard from him.

Mr Gibson, a corporate financier, thanked police and said he would return to Cambodia in September.