A few years ago, Cambodia's ruler launched the most ruthless crackdown of his career to annihilate his opponents.

Facing popular opposition, Hun Sen used the courts to dismantle the political party threatening his rule. Ranks of MPs were thrown out of parliament while the leaders were arrested.

Having crushed his rivals, he cruised to victory six months later at the 2018 election, winning all 125 seats in Cambodia's parliament.

For voters heading to the polls again this Sunday - it's déjà vu with their only alternative banned.

"It's a rigged election because there are no real strong opposition parties," one voter, an aid worker in Phnom Penh, told the BBC.

Hun Sen, now 70, has ruled Cambodia since 1985. A former Khmer Rouge official who defected to Vietnam before the regime's fall, his survivalist grip on power has led to his boast that he is the world's longest-serving prime minister.

For nearly 40 years, he has consolidated power through a network of interests, including the military, police and intelligence groups.

He has seen off opponents over the years by co-opting, jailing, exiling or otherwise side-lining them.

The UN set Cambodia up to be a democracy in the 1990s after the horrors of the Khmer Rouge regime. But political analysts say it's now an authoritarian one-party state, and Hun Sen is by most standards, a dictator.

"I feel hopeless for the current situation," the voter in Phnom Penh said. A decade ago in his early 20s, he had voted for the opposition, impassioned by thoughts of change.

But Hun Sen crushed that movement. These days there is fear around criticising the government at election time.

Cambodia remains one of the poorest countries in Asia - and locals are struggling with fuel prices and stagnant wages. Corruption is endemic, public accountability weak. Land grabs and rising crime make life even more intolerable.

But everyone knows that in Sunday's vote, the Cambodian People's Party (CPP) will win again.

"This will lead to no representative voices in parliament that can speak about the problems of the people, who can protect the interests of the people," the voter said.

"That's why the people have remained silent this time around."