Kennett said the family was disappointed Ricketson was not even given the opportunity to hear the decision. "We were very hopeful that James may be able to live in conditions appropriate for his age," she said. Mr Ricketson's son Jesse Ricketson, who has moved to Cambodia to assist his father with the case, said: "Our family is sorely disappointed by today's verdict. We had all hoped very much that the court might return a positive result on the question of bail, allowing my father to sit through the investigation period in conditions more appropriate to his age." "As he's almost 70, our family is very concerned about my father's health in the lead up to the hot period in March and April. He has already lost 10 kilograms and is currently housed in a cell the size of 16 metres by six metres with 140 other men and we're just not sure how long he can endure these conditions," he said. Loading

James Ricketson's family have appealed to the Cambodian Government to help ensure the investigation be carried out with transparency and due process: "We hope that if there is evidence of James' crime, it will be brought forward swiftly, or, if there is none, that he be released accordingly. "James is an excellent and loving father, uncle and brother. He is a kind, decent and honest man, and has, over the last 22 years, volunteered a lot of his time and money to help poor families in Cambodia. We firmly believe James is innocent of espionage or any other crime and hope to see him return home soon." Jesse Ricketson said the toll on the family is enormous: "All his family and his many friends have rallied and are assisting James in whatever manner they can, the impact is not on James alone, but rather all of us. "As always we are hopeful for the compassion and consideration of both the Australian and Cambodian governments in bringing about a conclusion to this incredibly difficult situation." Fears are held for the health of Ricketson who is sharing a cell with 140 other prisoners in Prey Sar, an overcrowded prison on the outskirts of Phnom Penh.

Ricketson faces up to 10 years in jail on espionage charges that lawyers say relate to his alleged links to the country's now disbanded opposition party which has been accused of attempting to overthrow strongman Hun Sen in a purported United States-backed conspiracy. Opposition leaders who are in jail, have fled the country, are in hiding, or the US deny any conspiracy. Diplomats and analysts in Phnom Penh say the claim has provided Hun Sen, one of the world's most notorious autocrats, with an excuse to target his political opponents as he shrugs off any pretence of democracy. Ricketson has for years filmed opposition rallies and events in Phnom Penh while supporting scavengers at a local rubbish dump. He also has been making a film on a former street beggar he adopted as his daughter.

Ricketson told an earlier court hearing he came to Cambodia "to help poor people and make films, not to be a spy". More than a dozen police carried him away from Phnom Penh's waterfront hours after he was photographed flying a drone over a political rally by the opposition Cambodian National Rescue Party. "I am still confused as to what I have done other than flying a drone without a permit to deserve such punishment," Ricketson wrote from his cell last year. Authorities have released vague details of the accusations against Ricketson, referring only to spying for a "foreign entity". Official say they are translating thousands of emails found on his computer into the Cambodian language.

Ricketson suffers unmedicated high blood pressure and other ailments. Ms Kennett said conditions in the prison are "not good". The rejection of the bail applications leaves Ricketson facing months, if not years, in jail pending a possible trial. He has not yet been formally charged while prosecutors and a lower court investigate the allegations against him. In Australia more than 60,000 people have signed a petition calling on the Turnbull government to intervene in the case.

But the Department of Foreign Affairs says it cannot interfere in the judicial system of another country.