When I was a child, I didn’t read. In all honesty, no story was as exciting as the fairy tales my mother told my siblings and me. A story that captivated my childhood imagination more than anything else was about a magic cudgel that granted any wish, as long as you wished with a good heart; I could daydream about holding that omni­potent object in my hand and forget about everything else. The early years of school in North Korea could offer nothing but the narrative of the Supreme Leader’s childhood, which all North Korean children learned according to their age group, growing up alongside him. The Revolutionary History of the Leader Kim Il-sung did not captivate me as the magic cudgel did, and I performed poorly at school.

However, as I progressed through school, the demands of achieving good grades grew stronger and I had no choice but to immerse myself, like everyone else, in the Supreme Leader. My mother tongue – the one that I learned to read write, think in and understand the world through – was the language of our Revolutionary History. Even when I turned to novels or poetry, whatever book I opened, it was the same: the Korean language served to tell the story of two protagonists alone, Kim Il-sung and Kim Jong-il. Even “everyday heroes” were unrealistic people, swearing absolute loyalty only to the Supreme Leader and the Workers’ Party, and they were not people I wanted ever to resemble.

I had the rare privilege to study western music from the age of seven – cassettes of Dvorák were smuggled in from China by my piano teacher – and I could not find any literature that spoke to me in a way that approached what I experienced through this thrilling and complex music. But what gave me aspirations to become a writer was the poetry of Byron. In North Korea, gaining access to any foreign culture is a crime of “revisionism”, but there is a “hundred copy collection” (each book limited to a hundred copies) available to the elite, so that they might receive a cultural grounding to help them carry out their jobs as leaders, diplomats and propagandists. I don’t know how one of these limited editions of Byron’s works ended up in my father’s personal bookcase, but that is where, aged 15, I found it. For the first time in my life, tears welled in my eyes as I read a book. The words contained emotion as a melody and the plots of the poems were like the resonance of an orchestra in a hall. I was relearning my own language from a foreign book.

In the strict apartheid of North Korea, the use of language is tightly controlled across different classes of people. Above all, the language used for reference to the Supreme Leader is set apart in its grammar and vocabulary. Kim Il-sung is always “great”, and “greatness” must always belong to the Supreme Leader alone; but Byron taught me that the word could be used to describe any one of us, and that every one of us could dare to partake in such qualities. I wanted to become Byron, not only as a writer, but also as a man who might consider risking his life for an ordinary beloved – and not just for the Supreme Leader. I grew self-righteous, gloating at the thought that all the North Korean writers before me who had no access to Byron were like frogs in a well.

There could exist no such novel, poetry or story created by a North Korean writer. All forms of culture remain under the law of Kim Jong-il’s “Juche Art Theory”, which dictates that all North Korean literature must be in the style of “socialist realism”, with “socialist” denoting not an ideology, but an interpretation of “reality” dictated by the regime: a reality in which the Supreme Leader’s Revolutionary History must be the only truth. The world may talk about the counterfeiting of dollar bills by the regime for the sake of maintaining its grip on power, but this regime has set up a more invidious system for the purpose of counterfeiting the thoughts of its people. This not merely influences or interferes with their most intimate thoughts, but enforces a state policy to fabricate them from conception to expression, from each individual to the consciousness of the nation.

As an employee of the United Front Department (UFD), I witnessed this project at first hand. The UFD is a hybrid entity for policymaking, espionage and “engagement” with the outside world that functions as a controlling body to project and reflect perceptions of North Korea. I worked in Section 5 (Literature), Division 19 (Poetry) of Office 101. Despite the uncanny and unintended echo of Orwell’s Room 101, this office was, ironically, so named precisely in order to avoid any hint of the nature of our work. When it was first set up, the department specialised in conducting psychological warfare operations against the South through cultural media such as the press, literary arts, music and film. After the 1970s, it strove particularly to amplify anti-American sentiment and foster pro-North tendencies among the South Korean population, exploiting the democratic resistance movements that had risen against the then military dictatorship.

My task, like all other writers in the system, was to express an institutional line, not an individual message. No writer in North Korea is permitted to act beyond a bureaucratic affiliation that controls the process – from the setting of the initial guidelines for each work to the granting of permission for publication – through strict monitoring, evaluation and surveillance. Our main task was to transform ourselves into South Korean poets who supported Kim Jong-il. My South Korean pseudonym was Kim Kyong-min. This is the only way to earn recognition as a writer in North Korea: under a name that is not your own.

Elsewhere in the world and throughout history, the subject of literature has included the human condition. But under the suffocating constraints of North Korean surveillance, where the only concerns permitted in artistic expression are those of the Supreme Leader, I could not produce any writing that allowed me to feel I was accomplishing anything other than a bureaucratic task. Despite this, my colleagues in the propaganda departments envied me. Because I worked under an assumed South Korean identity, I did have some licence to experiment with straying from the legal bounds of North Korean art – at least in the exercise of style. This provided the “freedom” in which I composed my work; which, paradoxically, stood out from writing by my more careful and devout peers and led to my being admitted into Kim Jong-il’s inner circle.

In December 1998 I was given the job of writing an epic poem that would promote the notion that the North Korean policy of songun – the project to unify the entire Korean Peninsula through the superior might of our military force – had been formulated to protect South Korea. My poem, “Spring Rests on the Gun Barrel of the Lord”, was written in the voice of a South Korean poet who, recalling a massacre of activists in his own country, visits Pyongyang and finds protection and peace there. It so pleased the Supreme Leader that it was distributed throughout the nation and, in 1999, aged 28, I was made one of his six poet laureates.

Becoming one of the “Admitted” invol­ved attending a dinner with Kim Jong-il, who played with his white Maltese puppy and kicked off his shoes (high-heeled, with an inner platform at least six centimetres high) under the table. That night changed the course of my life in a way that winning the lottery might do in a capitalist nation; but, more importantly, it granted me immunity. Not even the highest authorities in the DPRK could investigate, prosecute or harm one of the Admitted.

Unless, that is, they committed treason – which I did. I lent a friend a restricted book, the contents of which included a biography of both Kim Il-sung and Kim Jong-il written by a South Korean academic. In discussing the infidelity and violent purges in the Kim family, this book starkly contradicted the official Revolutionary History. When the authorities found out about my transgression I had no choice but to escape to South Korea.

I know that no dictatorship can be successful merely by force. A dictator may use a form of religious cult to demand an unquestioning and heartfelt obedience from each individual, or a myth of racial superiority to bind the loyalty of many to one selfish cause. North Korea is no exception in the modern history of totalitarianism. There are the brutal political camps that physically shut away the lives of North Korean people; but there is also a dictatorship of the mind, the political prison where thought and expression are stifled. North Korea’s dictatorship of force over its people – its police-state system, the inescapable surveillance, the party’s invocation of the “Supreme Leader’s will”, overruling even the national constitution – cannot end while the dictatorship of the mind prevails.

The only power that will undermine the dictatorship of the mind is the realisation that it is possible not only for the regime to lie to its people, but that it has done so, deliberately and constantly. My people cannot be free until each of us acknowledges that the Revolutionary History of the Leader is not the true reality of North Korea.

“Dear Leader” by Jang Jin-sung, translated by Shirley Lee, is published by Rider Books (£20)