GENEVA (REUTERS) - North Korea's best-known defector, Mr Shin Dong Hyuk, dreams of making the "impossible" happen one day - ridding his secretive homeland of the kind of brutal prison camps he says he was born and raised in before a dramatic escape in 2005.

Mr Shin met senior human rights officials in Geneva this week to discuss a United Nations (UN) investigation into alleged crimes against humanity in North Korea, and said he would bear witness to the horrors of his life in Camp 14 to help build an eventual criminal case against North Korea's leadership.

But in an interview hours before he was due to receive an award from the activist group UN Watch, the 30-year-old was under no illusions about the scale of the task he and others faced in their search for justice.

"Maybe they can make the impossible possible," Mr Shin said of the inquiry, launched by the UN Human Rights Council, which aims to gather enough information from camp survivors and other exiles to document violations including torture and executions.

"They need to do it from a long-term perspective and in a very systematic way," he said, speaking through an interpreter."I will do my best, whether it is giving testimony or having other interactions with them."

He vowed to keep speaking about the shadowy political prison camps across North Korea, which rights groups say hold some 200,000 inmates forced to work in farms, mines and factories.

Pyongyang denies the existence of the camps in the isolated country and says it will not cooperate with the UN probe.

"This is something I should do, let the whole world know the situation in order to help get rid of those camps," Mr Shin said.

"Actually on a gut level what I want is for the world to send... troops who would save all the political prisoners in the camps, or something like a major breakthrough which is impossible right now," he said, sipping a Coke in a cafe.

GENERATION OF WITNESSES

Mr Shin was due to address the European Parliament in Brussels on Thursday, and is one of a new generation of North Korean defectors stepping into the limelight to tell their personal stories to highlight rights abuses at home.

A slight man with glasses, Mr Shin has said that he endured starvation, beatings and torture including being suspended from a hook in the ceiling and lowered over a fire which left burns.

He is roughly the same age as North Korean leader Kim Jong Un, and lives in Seoul, South Korea, after escaping from his homeland via China eight years ago.

But unlike the privileged heir, his first 22 years were spent in harsh conditions with 20,000 to 30,000 other political prisoners in Camp 14 in Kaechon, South Pyongan province.

Life was bleak, marked by food deprivation and horrors.

"For example beatings and being punished, usually by hunger, and public executions. Those are the things we grew up with.

"The reason for public executions was quite vague, sometimes it was not known. Sometimes they were executed for theft, sometimes for escaping from prison," Mr Shin said.

Escape from Camp 14, by Washington Post journalist Blaine Harden, tells his harrowing story. In it, Mr Shin admits to having denounced his mother and older brother for trying to escape.

His mother was hanged, his brother shot by a firing squad.

He watched their executions with his father, whom he left behind when he fled nine years later a day after New Year's.

"There were a lot of fences, including electric wires. An inmate who tried to escape with me failed (and died). I was almost electrocuted," he recalled of his escape in the snow.

Mr Shin headed north in a stolen soldier's uniform, taking a month to reach China. He bribed border guards with cigarettes.

"That was nothing special back in 2005, so many people were crossing the border at that time. Ordinary North Koreans who were hungry. Now security is really tightened," he said.

He voiced concern at the fate of nine young North Korean defectors, believed to be orphans, whom the UN said last week were sent back by China to their homeland.

"I feel sad because when they were sent back to North Korea they must be subject to harsh treatment and beatings and they could even be sent to a political prison camp," Mr Shin said.