Did you always want to be an artist?
No. I decided to become an artist in the late 1970s to try to escape the totalitarian conditions in China. Everybody wants to be part of the big power, so there are lies and false accusations everywhere. For me, art is an escape from this system.
If you were not an artist what would you be?
Is there a distinction between your art and your activism?
Art and politics are fragments of the same thing – they're about an understanding of our surroundings. Sometimes my work is political, sometimes it is architectural, sometimes it is artistic. I don't think I am a dissident artist; I see them as a dissident government.
Your twitter account (@aiww) has 48,000 followers and you usually tweet over 100 times a day. Why?
For the first time in over 1,000 years, Chinese people can exercise their personal freedom of expression. This is down to Twitter, which has become part of my life in the same way that art has. They are inseparable. I also like Twitter because it creates possibilities for us to reach out to feel hope, otherwise we are all just individuals and cannot share the same kind of dream or same kind of gaze in another person's eye. It's a little bit of light in a dark room.
Has your interest in politics overtaken your interest in art?
My art works best when there is an underlying political theme. I want all of my political efforts to become art. I also feel a responsibility to speak out for people around me who are afraid and who have totally given up hope. I want to say: you can do it and it is OK to speak out. But it isn't necessarily deliberate, it's just how I am.
You claim that police entered your hotel room and attacked you because of your involvement in reporting the names of students who were victims of the Sichuan earthquake in 2008. Has this forced you to change the way you work?
No, I haven't changed anything about the way I work. And I don't plan to. The attack almost ended my life, but this work will always be worth the effort if I can make a strong voice and readjust living conditions for the people around me. I will always feel sad when students are killed and nobody takes responsibility.
People describe you as the leading Chinese artist fighting for freedom of expression.
It is difficult, though. The ideology in China doesn't encourage freedom of speech. There isn't even freedom of information – everyone knows that the Internet and newspapers are heavily censored in China. I think that all artists should stand for certain values, particularly freedom of expression. It is the most important issue we face in China, yet hardly any Chinese artists concentrate on this. Maybe artists in the west don't have to fight for this, but democratic societies have other problems.
How do you view China's development since your childhood?
New technology has forced China to put itself in a more open position. But this has not been done willingly by the government. Politically they want the structure to be the same as it was when I was growing up. Although everyday life has become better for most people, there is still a lot of work to be done. People are too cautious of the potential crisis. We all need to take more responsibility for the political situation.
Are you optimistic about China's future?
In the long run it is not possible to stop Chinese people speaking for freedom and democracy. Living in China can be very frustrating, but also very exciting. You see the possibilities and play the game.
Is there a plan?
Are we all doomed?
I am not optimistic about the future. Our whole lives have been designed by fate. And although some humans are brilliant, everything looks like it has already been settled.
Interview by John Sunyer
Ai Weiwei's Unilever exhibition is in the Turbine Hall, Tate Modern, London SE1, until 25 April 2011.
Ai Weiwei: defining moments
1957 Born in Beijing to Gao Ying (mother) and Ai Qing (father), who is often cited as the most influential Chinese poet of the 20th century
1978 Joins the Beijing Film Academy
1981 Moves to New York; leaves in 1993
1995 Produces controversial artwork Dropping a Han Dynasty Urn
2008 Boycotts the Beijing Olympics, despite helping to design the "Bird's Nest" stadium
2009 Produces Remembering 2009 to commemorate the 2008 Sichuan earthquake, a wall of Chinese text covering the façade of the Haus der Kunst in Munich, Germany, made up of thousands of children's backpacks
2010 Becomes the 11th artist to show in Tate Modern's Turbine Hall