Promised better-paid jobs across the border in Thailand, Cambodian men are being kidnapped by gangs of traffickers and sold onto illegal fishing boats that trawl the Gulf of Thailand and the South China Sea. For two years Chorn Theang Ly was kept at sea under armed guard. He describes how his quest for a better life turned into a nightmare.

I live in the village of Anlong Khran in Cambodia. One day a man came to the village and said we should go to Thailand as we would have a much easier life there. Here, we work in rice fields, growing our own rice and vegetables. We make up to $200 a year. The man said we would make a lot more than that in Thailand.

He took a dozen of us over the border. We paid him 7,000 Thai baht for this – 3,000 for the transport plus a month’s worth of our pay. He said we would work on the riverbank, in factories, and have a much better life.

When we got to Thailand he took us to a house. Suddenly we were locked up inside it, all of us together in one room. It was only then that I realised that we had been sold. We tried different ways of escaping, all of us, but we had no money, passports or papers; there was nowhere for us to go.

We stayed there all night. Then, at about 4am, we got a wake-up call. Some men took us to a fishing boat, and that’s when I realised what would happen to us. We had been trafficked. It was too late to do anything. We were powerless.

At sea, we all got seasick. I remember it got so bad for me that I was vomiting blood. As a group we decided we would stick at it for one month, earn our wages and then somehow get back to Cambodia.

The boat’s owner told me we would have to work for him for at least three years. I found out that there is a whole system at work: a good employer lets you go ashore after eight or 10 months and pays you off, but a bad one will keep you at sea for three years and not pay you anything, or just a token amount.

Conditions on board were very hard for us. We worked all hours of the day, and there was little food or fresh water, just one small bucket. If we got a big catch we’d have to work day and night, slicing and gutting fish. If there was a torn net we would have to work for two or three nights without sleep to repair it. Another boat would sometimes meet us to take the catch and give us more food and water. We scarcely saw land.

I saw killings too, with my own eyes. There were three Thai crew on board and they were all armed. The captain would physically abuse us. In the early days he beat me nearly unconscious. He would beat us with the tentacle of a squid or sometimes a large shell. The man I saw killed was beaten and then thrown overboard. Another time, a man was shot and his body thrown into the sea.

We were constantly plotting to kill the captain and take the boat ashore. But the crew had guns and we knew we couldn’t do it.

I was transferred to other boats after that first one. In the end I was at sea for two years. Finally, when a boat I was on put ashore in Thailand I persuaded them to let me go. They took me back to the border in a truck and left me there. With the help of one of the traffickers I got back across the border into Cambodia.

There are many people from my area who still want to go to Thailand. I tell them about the cruelty and the lies, but they are determined. The problem is there is so little to do here. We used to make money from charcoal, cutting and burning trees, but the government stopped that for environmental reasons. How else are we supposed to make a living?

• Chorn Theang Ly was talking to Jonathan Gorvett in Cambodia.