Ji Young Lee (29) saw her first dead body when she was still a child. She was nine; it was lying on the street, covered in flies. "Nobody was bothered", she recalls. "Back then, there were dead bodies all over the place: at the station, on the streets. People were dying of hunger." Next to her, Sung Kuk Choi (36) nods.

Lee and Choi are refugees from North Korea. They escaped six years ago to South Korea via different routes. Lee is reading Human Rights Law and Choi is a well-known cartoonist, one of the first from North Korea. He creates comics about the differences in culture between North and South Koreans.

Last week, they travelled through Europe with the South Korean non-profit organisation National Students Council of NKHR to draw attention to the plight of their birthplace. On Thursday, they addressed a lecture hall full of Leiden students and had time to talk to Mare afterwards.

They both lived through the "Arduous March" as children, the famine that struck the dictatorship between 1994 and 1998 and left – estimates vary quite a lot – between 250 thousand and 3.5 million Koreans dead. Economic mismanagement combined with a series of floods, periods of severe drought and the loss of aid from the Soviet Union meant food supplies ran out.

Lee remembers: "My mother was disabled and didn’t have full use of her legs. I was responsible for my little brother and sister. We sometimes ate grass from the mountains or I resorted to stealing; guards would beat me if they caught me. But hunger was my enemy and my only mission was survival."

"They turn people into complete idiots", says Choi about the North Korean government. "People depended on the distribution system and didn’t know how to find ways to get their own food. They were used to being dependent on the regime’s rations. It was illegal to create your own market. That’s how they kept the system going.

"Things have changed a little bit. They smuggle produce from China and create black markets to survive. A kind of capitalist market has emerged, and that’s why you see more things that go with it, like differences in income. There’s more information from outside, too. So it is better than it was, even though everyone is watched very closely."

They are from different worlds: Lee was born in the country, while Choi attended the Art Academy in the capital, Pyongyang. "It’s a bit embarrassing", he says, "but I bought my way in. I didn’t want to study."

He’s been in prison three times, for a total of nine months. "For distributing South Korean DVDs. There were rapists and thieves, but I was the worst criminal there because I had passed on information from the world outside."

Sung Kuk Choi draws a square on the blackboard in the hall; it has a little figure on a pole in the centre.

"That’s how they do things in North Korean prisons: the prisoner sits on a concrete pillar in the centre of the cell. The floor is flooded and has an electric charge. You can’t sleep and when, after three days, you fall off it from exhaustion, you get an electric shock that wakes you up again. Then they put you back on the pillar. After a while, you’ll confess everything."

For Choi, the decision came when he was banned from Pyongyang and sent to the country. "The rest of the country is a century behind the capital. I thought we never paid tax, but in the country I had to pay one fee after another. And everyone was always being re-educated about the system. I complained because it was so different from Pyongyang, but people said I should forget about my life of luxury.

"I realised that there were two laws for the same nation. Life in the country was terribly harsh. There were three or four layers of control; we were watched all the time. Everyone around me played a role; there was no sense of community."

Lee joins in: "Pyongyang exploits the countryside. He discovered that because his life had changed so much. But most people are not aware that fleeing is an option. It took me a long time to realise it too."

Lee worked as a telephone operator for the Ministry of State Security until she was fired seven years ago. "I was extremely proud to work for one of the most important organisations in the country, but all of a sudden I received a letter that I had been fired: my mother had fled North Korea. She had bribed soldiers on the Chinese border and told them that she was only going to China on business and that she would return soon. Instead, she went to a relative who already lived in China. With help there, she travelled to South Korea, which made her a traitor. And so I, a member of her family, was guilty too. Suddenly, I had to be careful of everyone, you can’t imagine.

"I had been brainwashed from an early age. Even after I’d been fired, I thought I should work harder to acquit myself. If war had broken out, I would have killed Americans for Kim Jong Il because I blamed them for the bad situation."

About then, in 2009, the currency in North Korea devaluated, causing hyperinflation and so food prices soared. The money received by families, 100,000 won per unit, instantly became worthless. "It was just old paper. Rice became a hundred times more expensive than it had been. I decided to leave too. I realised that I had always seen things the wrong way. It’s difficult to find a way out of there, but my mother helped me. She paid all the smugglers.

"There are lots of people who want to flee, so more and more smugglers emerge to meet the demand. They sell North Korean women to China – because there are lots of old, unmarried men who can’t get a wife. Luckily, a relative helped my mother and my mother helped me."

Choi fled, but won’t say how. "Because I might put future refugees in danger." He now helps North Koreans across the border, too, he says, as he draws North Korea on the board. "The country looks like a gun", he points out. "Most people flee via the north. They go through China, to Laos and then on to Thailand. In China, they might arrest you and send you back. And sometimes North Korea bribes the government in Laos. In Thailand, you ring up South Korea and they advise you to get arrested by the police. Because, instead of sending you back to North Korea they send you to South Korea. It takes more than a month in all.

"You can go via the south too, which means taking a boat from the eastern coast. It only takes eight hours, but it’s more dangerous. Fleeing is so expensive. Many people have to borrow money from the smugglers, so you start off with a debt."

Both of them are now dedicated to the rights of their fellow countrymen. Lee wants to graduate first and Choi tries to smuggle information into the country using things like huge balloons filled with USB sticks. "Sending documents about human rights doesn’t work. Love stories, stories about families, that sort of thing does."

Lee adds: "South Korea is like another planet. I had some cash on me when I arrived. They advised me to put in the bank. You have to feed it into a cash machine but I was too frightened. I thought I would never see it again."

"How naive!" Choi smiles. Lee continues: "I thought I had to be loyal to the President of South Korea. But then I met some South Koreans who criticised their own government. That’s inconceivable for North Koreans. I thought: won’t the nation collapse?

"Do you know what I liked?" asks Choi. "When I went to the loo for the first time and I had to wash my hands. The taps were automatic so you didn’t need to turn them on. I’d never seen anything like that before. I stood there and I thought I had to give the tap an order. So I said: ‘Give me water.’ And it did! And nobody said anything."

A page from Sung Kuk Choi’s new book. Sung Kuk Choi writes comics about the differences in culture between North and South Korea. In this comic, North Koreans visit a doctor in South Korea.

Frame 1: "I’m going to take a blood sample. Please enter one by one!

Frame 2: "Blood? Why?"

"Is what he told us about it true?"

Frame 3: On the sign: "Brutality of the North-Korean regime"

Frame 4: North-Korean officer: "In South Korea, they distract you with pretty ladies and take all your blood and remove your organs to sell them!"

Frame 5: "No! That’s just what they used to tell me! I don’t know either!"