Australian filmmaker James Ricketson, who has spent seven months in Cambodian prison awaiting trial on “espionage” charges, made an impassioned plea for release yesterday, saying the case was “absolutely” political and that there was no evidence to suggest he was guilty of spying.

Arriving at the Supreme Court with his orange jumpsuit soaked with sweat, Ricketson decried the conditions of his detention. He was there to appeal two prior rejections of his bail requests.

“I’ve just been beaten up by the police at Prey Sar prison. There’s no evidence that I’ve done anything wrong,” he told reporters. “We’re transported in a tin can – with no water, no air conditioning. This is the kind of torture that’s inflicted on you whether you’re innocent or guilty.”

Ricketson was arrested in June after he was spotted flying a drone above an opposition party rally ahead of the commune elections. Months later, the leader of the Cambodia National Rescue Party was arrested for “treason” and the party was dissolved – a move that analysts say discredits the upcoming national elections.

Ricketson was held for several days without charge and, he claimed in court today, was informed by immigration police that they had found no evidence of espionage on his seized computer, mobile phone or four cameras after they were “forensically tested”.

“When it became apparent that there was no evidence that I was guilty of espionage, I should have been released immediately,” he told the Supreme Court judges.

“I requested that I be at least told the country I was spying for – was it Australia, the US, France? Which country?”

Phnom Penh Municipal Court Investigating Judge Pich Vicheathor requested Ricketson be held for up to six months more in pre-trial detention while he combed through the Australian’s emails.

Lou Rabo, the deputy municipal police chief in charge of immigration, refused to name whom Ricketson was allegedly spying for, and further denied he had been told there was no evidence.

“All the evidence we found we have already submitted to the court. Now it’s up to the court,” Rabo said.

Ricketson said his case was “absolutely” political.

“For six months, my face and name appeared on state-controlled media implicating me, along with the CNRP, of being involved in a conspiracy to conduct a colour revolution,” something that Ricketson characterised as “a perversion of the course of justice”.

Government mouthpiece Fresh News, for example, has republished several unsubstantiated articles, one of which linked Ricketson to an alleged US-backed plot involving opposition members to overthrow the government.

“It’s unreasonable in my view to hold a 68-year-old man for seven months because I flew a drone without a permit,” he said, adding the case had “no witnesses, no complaint and no victim”.

He also denied he was a flight risk as he had a dependant adopted family in the Kingdom.

“The court has my passport. I can’t leave the country unless I swim across the Mekong. You have $50,000 worth of my film equipment as surety,” he said.

His lawyer, Peung Yok Hiep, stressed that “if released on bail, my client will not do anything affecting social security”.

“He is innocent. The information he collected was only for cinema and to help the poor children in Cambodia. He collected information, but not to damage the national security,” she said, referring to the specific charge against him.

Alexandra Kennett, the partner of Ricketson’s son, was present for his hearing yesterday and said they were “hopeful” the bail application would succeed, or at the least that his trial could proceed swiftly.

“We’re deeply concerned for his health and wellbeing. We’re appealing to the compassion of Australia and Cambodia to resolve this situation as quickly as possible,” she said

Ricketson’s case gained increased interest in his native Australia over the past month, with an online petition for his release now having more than 30,000 signatures, up from about 6,000 last week.

He is a controversial figure, however, with NGOs like the child protection group APLE and the Cambodian Children’s Fund claiming he made unsubstantiated allegations of abuse against them. His supporters have lauded his charity work, but the Cambodian courts have previously fined him for defamation and blackmail.

A decision on Ricketson’s bail application will be made on January 17. He is also due to be questioned by the investigating judge at the municipal court on Friday in relation to his emails.

Additional reporting by Kuoch Masy