Not only did I believe that humans were selfish and base, I also knew that plenty of them were actually bad – content to destroy lives for their own gain. I’d seen Korean-Chinese expose North Korean escapees to the police in return for money. I’d known people who’d been trafficked by other humans as if they were livestock. That world was familiar to me. All my life, random acts of kindness had been so rare that they’d stick in my memory, and I’d think: how strange.

Kindness toward strangers is rare in North Korea. There is risk in helping others. The irony was that by forcing us to be good citizens, the state made accusers and informers of us all.

The school year started in September, with a long vacation in the winter, not the summer, due to the difficulty of keeping the schools warm in North Korea’s harsh winters. My kindergarten had a large wood-burning stove in the middle of the classroom and walls painted with colourful scenes of children performing gymnastics, children in uniform, and of a North Korean soldier simultaneously impaling a Yankee, a Japanese and a South Korean soldier with his rifle bayonet.

I had to learn Mandarin. And I had the best teacher – necessity. You can study a language for years at school, but nothing helps you succeed like need, and mine was clear, and urgent.

It was an aspiring neighbourhood that retained a faint edge of slum, typical of Shanghai. Pensioners in Mao-era padded jackets would sit on doorsteps playing mah-jong, oblivious to the Prada-clad girls sweeping past on their way to work.

This is the first time I will tell my story in English, a language still new to me. The journey to this moment has been a long one.

In North Korea the only laws that truly matter, and for which extreme penalties are imposed if they are broken, touch on loyalty to the Kim dynasty.

As many discover, freedom – real freedom, in which your life is what you make of it and the choices are your own – can be terrifying.

It was at school in Hamhung that I received my initiation into ‘life purification time’, or self-criticism sessions. These have been a basic feature of life in North Korea since they were introduced by Kim Jong-il in 1974, and are the occasions almost everyone.

Behind the bluster, I sensed fear. Dictatorships may seem strong and unified, but they are always weaker than they appear. They are governed by the whim of one man, who can’t draw upon a wealth of discussion and debate, as democracies can, because he rules through terror and the only truth permitted is his own.