This BBC story looks at how the Cambodian government is growing ever more intolerant of dissent.

An excerpt:

The United Nations Special Representative to Cambodia on Human Rights, Yash Ghai, believes it is time for the world to worry about the direction Cambodia is taking.

"The people of Cambodia are deeply committed to human rights precisely because they have suffered so much from the denial of those rights," he said.

The opposition is in disarray without its leader Sam Rainsy

"The government here seems to think that human rights are a nuisance. They identify opposition groups with human rights. I am hoping that in my time here I can persuade the government of the value of human rights"

The government has had an adversarial relationship with Kem Sokha since he founded the Cambodian Centre for Human Rights three years ago. But the events of New Year's Eve marked a serious escalation of that conflict.

The rights worker was arrested and charged with defaming the government because of a banner displayed at a rally to mark International Human Rights Day in December.

The banner accused the government of selling land to Vietnam, following the ratification of borders between Cambodia and Vietnam which were originally set during the Vietnam-backed regime of the 1980s, and which some people feel lost Cambodia land.

One of the rally's organisers received similar treatment, and a few days later one of Kem Sokha's colleagues was also arrested and charged.

It was the second round of arrests of government critics in recent months. In October, the government brought charges of defamation and incitement against seven people who also criticised the proposed border treaty.

We advance some steps, we go back - it's like a dance, a cha-cha-cha - I'm so sorry about that Kek Galabru, president of Licadho human rights group

Five of them left the country before they could be arrested, and other critics of the government also fled as rumours swirled around Phnom Penh.

Defamation is a criminal offence in Cambodia, a legacy of the United Nations transitional regime in the early 1990s. Critics say it was a law for exceptional circumstances that should have been replaced by now.

The government, however, has defended its right to prosecute those whom it says have broken the law. The chairman of the government's Human Rights Committee, Om Yen Tieng, insists the government is tolerant of criticism, but not when it amounts to defamation.

"We never jail any of the guys who criticise the government. They're still free. We put in jail people who abuse the law," he said. Some NGO workers say the government has become increasingly intolerant to criticism over the past year. International attention has largely been focused on areas such as Afghanistan and Iraq, and the West sees Cambodia as an ally in its efforts to combat terrorism.

At the same time, China has become the biggest investor in Cambodia, and asks few questions about human rights issues. That means that the words of Western diplomats may carry less weight.