Chray Nhim knows what awaits her after Cambodia's national elections on July 28, when Prime Minister Hun Sen and his ruling Cambodian People's Party (CPP) are expected to consolidate their decades-long control of the country. Chray Nhim, a single mother of one, is bracing herself for the revenge she is certain will be meted out for her high-profile protests against forced evictions in the capital, Phnom Penh.

"I think I will be imprisoned after the election. I'm not scared; I have done nothing wrong. But I am worried for my daughter. She's nine and if I go to jail there'll be no one to look after her," says Chray Nhim. Lingering at the back of her mind is the thought that prison might not be the worst thing that happens to her.

"Maybe one day I'll be in an accident: a car will hit me. They might try and kill me for making so many problems for them."

She has every reason to fear for her safety. In Cambodia, the fast-growing number of land and labour rights activists and environmental campaigners are routinely singled out for harassment and arrest, or worse, by the authorities. In April last year, Chut Wutty, one of Cambodia's most prominent critics of environmental crimes, was shot dead. No one has been convicted of his murder. At least nine other land activists were killed in the decade before 2012, according to human rights organisation Global Witness.

Becoming an enemy of Cambodia's increasingly authoritarian government is not something Chray Nhim had anticipated. Until last October, the 35-year-old sold fruit from a stall on the streets of Phnom Penh and was not involved in politics. Then, she and the other 182 families living in Thmorkol village, a rubbish-strewn community of simple, one-storey houses and unpaved roads on the far side of the city's international airport, received a letter from the local council.

"It said that we had to move our homes 10 metres away from the airport fence within seven days or they would be demolished," says Chray Nhim. "They want to expand the airport.

"None of us were told when we bought the land that it was illegal to build here; the local authorities stamped my land documents. But we were told to move out and that we wouldn't receive any compensation."

The residents of the village had become the latest victims of the forced evictions that have resulted in 10 per cent of Phnom Penh's population losing their homes since 1991. Across rural Cambodia, an estimated 700,000 people have been thrown off their farms to make way for the so-called "economic concessions" that now cover 12 per cent of the country. The farms have been replaced by factories and vast sugar plantations owned by cronies of the CPP and foreign companies.

"The government tells people they have to leave in the name of national development and to beautify the city. But the land is used for speculation by private companies," says Ee Sarom, programme co-ordinator for Sahmakum Teang Tnaut, a local NGO that tracks the evictions and helps those displaced by them. "It's collusion between local government officials, investors and private companies. And those companies mostly have links to the CPP. They're either owned by politicians or their relatives."

One of the legacies of the murderous Khmer Rouge regime, which ruled Cambodia between 1975 and 1979, is that only about 20 per cent of Cambodians have titles to their land. The Khmer Rouge outlawed private property and mounds of paperwork disappeared in the chaos that surrounded the emptying of Cambodia's cities, as their residents were sent to work in vast agricultural communes. Without proof of ownership of houses or land, it is much easier for local officials to forcibly evict people.

But Chray Nhim and her fellow villagers do have land titles and, under her leadership, they decided to fight back.

"We demonstrated outside parliament, Hun Sen's house and the local council," says Chray Nhim, in the house she is still defiantly occupying. "Then I heard that Barack Obama was coming to Phnom Penh for a meeting. So we painted 'SOS' on the roofs of our homes and put up pictures of Obama. I thought he would see them when he flew into Phnom Penh and that it could help us find a solution."

Her inspired form of protest last November garnered worldwide publicity for the Thmorkol villagers and the other victims of forced evictions in Cambodia. But it also infuriated the government.

"I was arrested the day after we painted the signs. I was interrogated and told that what I had done was illegal and they threatened to take me to prison. The police wanted me to write a letter of apology to the Phnom Penh governor, but I refused," says Chray Nhim.

"My husband left after the 'SOS' protest. He was scared of confronting the local government and unhappy with me doing it. It's very difficult for us now. I've had to take my daughter out of school because I can't afford to send her anymore. I can't work because of the campaign to save our homes. Sometimes, we come back in the evening and we don't even have enough rice to eat."

Yet Chray Nhim has also been transformed by her new role as a full-time land activist.

"I'm definitely a different person to who I was before the protests. Before, I was just an ordinary woman selling fruit and had no idea how often forced evictions take place in Phnom Penh. I used to be shy about talking in public. Not now. I am stronger," she says.

Her political awakening is being mirrored across the country, as more and more ordinary Cambodians express their dissatisfaction with repressive rule. After 28 years in power, 60-year-old Hun Sen is the second-longest serving leader in Southeast Asia and in May vowed to stay in power until he is 74. But despite the CPP's iron grip on the judiciary, military and media, there has been a startling rise in dissent.

That discontent has been fuelled by the extreme inequality in Cambodian society, with a tiny elite prospering through corruption. The centre of Phnom Penh is now a flourishing haven of imported cars, new apartment blocks and shopping malls, but a third of all Cambodians still lack access to clean water. With Chinese, Japanese and South Korean investment flooding in, the economy is growing at a rate of 7 per cent a year. Much of the population, though, continues to live on just HK$8 a day.

"Cambodian politics have evolved from communism to neo-paternalism. It's gone in the opposite direction to a pluralistic democracy, as our 1993 constitution stated it should," says Lao Mong Hay, a Cambodian political analyst and former professor of Asian studies at Toronto University, in Canada. "It's about senior people enriching themselves at the expense of the country and then using their riches to consolidate their power. It's collusion between business interests and senior politicians, and that leads to land-grabbing and illegal logging."

Hun Sen and the CPP have been able to stay in power for so long by manipulating electoral rolls and intimidating and imprisoning opponents. Sam Rainsy, the best-known opposition politician, fled into exile in Paris in 2010 to avoid being jailed on what he and his supporters claim are trumped-up charges of destruction of property. Last month, the Committee for Free and Fair Elections in Cambodia said the upcoming elections were likely to be the most unfair since 1993, thanks to voter-list irregularities and a media completely dominated by the CPP.

Civil groups are in the vanguard of opposition to the CPP. People like Chray Nhim and her fellow villagers are forming themselves into community associations to defend their land, fight environmental crimes and campaign for labour rights. Even Cambodia's beer girls, the young women who patrol bars promoting breweries, have union-ised: many now proudly sport the patch of the BSIC - the Beer Selling Industry of Cambodia union - and are demanding fair pay and better working conditions.

Labour rights are increasingly an issue for the booming garment industry, too. Worth more than HK$30 billion a year, and employing at least 300,000 workers, textiles make up 80 per cent of the country's exports and four clothing factories open each month as Western companies look to Cambodia rather than China as a source of cheap labour. But strikes are an almost weekly occurrence as workers agitate for a rise in the US$80 a month minimum wage and contracts that guarantee them benefits such as maternity and sick leave.

"There is a real sense that there's a greater awareness by workers of their rights," says David Welsh, the Cambodia director for Solidarity Centre, an NGO that monitors the garment industry. "It's ironic that the higher levels of government and the brands themselves don't realise how aware their workers are. It's a result of the combination of their youth and work by the unions and the NGOs."

Almost two-thirds of Cambodia's population are aged under 30 - another by-product of the Khmer Rouge's genocidal regime, which was responsible for an estimated 2.2 million deaths. That young dynamic gives the recent surge in activism a real energy. Nevertheless, the rise of civil society is still a radical departure for Cambodia, a nation that has no history of it.

"Never before have there been groups agitating for social change in Cambodia. For a government that has been in power for so long, it's a worry. These people are voters and the protests create hesitancy in potential investors," says Naly Pilorge, director of the Cambodian League for the Promotion and Defence of Human Rights.

While labour rights and environmental abuses are attracting more and more attention, forced evictions and illegal land grabs remain the No1 source of anger among ordinary Cambodians. Most worrying for the prime minister is that he has been increasingly identified as being responsible for them.

"I blame Hun Sen the most," says Chray Nhim. "He is responsible for caring for the people. He shouldn't allow local authorities to do this to ordinary citizens. I know he is powerful but I am not scared of Hun Sen or the police. I would die to protect my home. I am the victim here; it's my house and land the authorities want to take."

Such defiance would have been unthinkable two years ago.

A former Khmer Rouge commander who lost his left eye in battle and was part of a faction who went into exile in Vietnam before returning after the Vietnamese army invaded Cambodia in 1979 to end Pol Pot's rule, Hun Sen is used to being obeyed. Hubristic to the point where he has been known to exaggerate his golf handicap, and self-conscious of his peasant roots, he is also ruthless enough to have disowned his adopted daughter when she came out as a lesbian in 2007.

MP Mu Sochua was one of only two female ministers in the government between 1998 and 2004, when she joined the opposition Sam Rainsy Party. She is well acquainted with Hun Sen's leadership style.

"We used to have meetings every Friday but they weren't cabinet meetings; they were 'listen to the PM' meetings. How can you discuss policy with a man who is so powerful? Ministers were scared of him. You had to please the big boss."

With the election fast approaching, the number of forced evictions has temporarily dropped.

"The CPP want to get re-elected, so they won't do anything bad to the people," says Chray Nhim. "But I think we will be evicted after the election; certainly by the end of the year. The only question is whether our protest will mean we get proper compensation."

For most victims of forced evictions, the process of losing their homes is much faster - and more traumatic.

"Often, they're given as little as a week's notice," says Ee Sarom. "The people are told that if they leave voluntarily, they'll get some compensation and be allowed to dismantle their homes and salvage their possessions. But if you don't agree to leave, then you get no compensation and your home is bulldozed."

Almost all the evictees end up in one of the squalid resettlement camps springing up on the outskirts of Phnom Penh. Close to 600 people from the nearly demolished Borei Keila neighbourhood of the capital have been relocated to Phnom Bat, a swampy, malarial field an hour and a half's drive northeast of Phnom Penh. They live in wooden shacks and one-room houses made of corrugated iron donated by an NGO. There is no electricity - they cook on open fires - and the only water comes from a well.

"We were given a week's notice to leave," says community leader Keo Vathy. "We weren't told why we had to leave; we were just told that our land is now owned by a private company. They demolished our homes in January 2012. Our compensation was a plot of land five metres by 12 metres here and between US$100 and US$500. But some families didn't receive any money and our houses were worth much more, up to US$8,000."

More than anything, being so far from the city means it is much harder for Phnom Bat's unwilling residents to find work.

"We call it 'slum creation'," says Ee Sarom. "It's a network of poor areas created by the government. They're making people move from poor districts, but ones with access to jobs and services, to areas where there's nothing. So central Phnom Penh is getting richer and richer while around the edges of the city are new poor neighbourhoods."

None of the evicted, or those from neighbourhoods threatened with losing their homes, will be voting for Hun Sen or the CPP in the upcoming election. Instead, the Cambodia National Rescue Party (CNRP), a coalition of the two main opposition parties formed last year, stands to benefit.

"Our entire community will be voting for them," says Chray Nhim.

Unable to advertise in the media and with polling station officials all members of the CPP, no one expects the CNRP to win the election. But the party is optimistic about gaining more seats in parliament. With the CPP mulling a new law that would drastically restrict the activities of community organisations such as Chray Nhim's, that may be crucial in the future.

"I think Hun Sen will target civil society if he wins the election," says Mu Sochua. "The more seats we win, the harder it will be for him to do that."

But the rise of grass-roots groups is already a warning to Hun Sen and the CPP that their time in power may not be unlimited.

"If you combine the official opposition with civil society organisations, unions, land activists and the people who have been affected by corruption, you can see many people mobilising and so I am optimistic about the future," says Mu Sochua. "I don't think even Mr Hun Sen believes he will rule for another 14 years. Look at what happened in Burma."