(Footage of police forcing a man into a van)
JAMES OATEN, REPORTER: A huge media contingent gathered to see one of their own taken away. Journalist and government critic Mam Sonando was sentenced to 20 years jail for leading an anti state rebellion in Kratie Province.
(People protesting the imprisonment of Man Sonando, holding large photographs of his face)
DINN PHANARA, MAM SONANDO'S WIFE (translated): The court accused him of secession and it is not true because he knows nothing about this. He has no idea why he was accused of being involved in such things. He doesn't even know Kratie Province.
JAMES OATEN: Sonando built up a strong support base due to his work with the independent radio station Beehive Radio.
(Interior of Beehive Radio studio)
The station is a channel for frustrated citizens to call up and vent. Now there are concerns the station's style of journalism will be silenced.
(Blurry footage and stills of beaten protestors and a dead journalist)
Cambodia has witnessed a series of attacks against activists, journalists and protesters this year. Last month, journalist Hang Serei Oudom was found dead in his car boot.
But the most prominent case was the killing of an environmentalist, Chhut Vuthy, who was shot as he escorted two journalists to a site where illegal logging was allegedly taking place.
(Footage of Chhut Vuthy's funeral)
Public pressure forced the government to open an investigation but earlier this month the case was dropped, with the court ruling the police officer who shot Chhut Vuthy was himself shot dead by a security guard.
(Protestors holding pictures of Chhut Vuthy)
SAM RAINSY, CAMBODIAN OPPOSITION LEADER: It is an authoritarian government, a very corrupt government, so the military, the armed forces are part of the system.
JAMES OATEN: Mr Rainsy is also facing persecution for alleged forgery related crimes, should he return to Cambodia.
But despite having to reside in France, he's refusing to be silent, having merged Cambodia's major opposition parties, he's now on an international campaign to pressure the government to reform the electoral system.
SAM RAINSY: There are several problems - the establishment of voter lists, the monopoly of the government, of the media, the electronic media, the intimidation, harassment and the atmosphere of fear and also vote buying.
The government controls everything in Cambodia. Opponents get killed, jailed, or forced into exile.
(Shot of the United Nations General Assembly report on human rights in Cambodia)
JAMES OATEN: Sam Rainsy isn't alone in his concern. In July a United Nations human rights envoy, led by Surya Subedi, released a damning report about the state of democracy in Cambodia.
The report recommends ensuring the national election committee be independent and autonomous, made up of retired senior judges and professors of law and politics.
Another committee should be established to ensure all major parties are granted equal access to state run media. It asks that the government clamp down on military and police officers intimidating people attending political meetings, and that finally, Sam Rainsy be allowed to participate in next year's elections.
(Hun Sen walking with entourage)
Prime Minister Hun Sen dismissed the recommendations, saying Surya Subedi should spend more time being concerned with his own country, Nepal.
But the statements have been welcomed by the Committee for Free and Fair Elections in Cambodia, with the organisation's executive director fearing a return to one party rule.
KOUL PANNA, EXECUTIVE DIRECTOR, COMFREL: The Cambodian people are concerned as we have experienced one party state control - our society, during the communist time and during the Khmer Rouge.
If we have no checks and balances between different political parties, especially ruling in opposition.
SAM RAINSY: Our current Prime Minister Mr Hun Sen has been in power for 33 years. Actually, he's the longest serving leader in the world.
JAMES OATEN: Hun Sen says he wants to remain in power as long as he's alive. And there's nothing to suggest an opposition will be able to overthrow the Government any time soon.
The Prime Minister is popular among rural communities due to his impoverished upbringing.
(Cambodian police restraining protestors and journalists)
But Sam Rainsy warns violence could prevail if Government maintains its hold on to power.
SAM RAINSY: If people stop believing in elections, there is no other channel to channel the popular discontent.
(Montage of protests in Cambodia)
JIM MIDDLETON: James Oaten reporting.