The leaders of Iran’s opposition Green movement — calling for political reform and evolution in society — have been under house arrest without trial for more than a thousand days: Mir Housein Mosavi, Mehdi Karoubi, and Zahra Rahnavard.

We spoke to Karoubi’s son Mohammad Taghi Karoubi, a law professor at the University of Westminster, in London.

Ali Khardpir, euronews: “Mr Karoubi, your father has been under house arrest since February 2011. The Minister of Justice and the Mayor of Tehran both said last year that this case is in the hands of the National Security Council. Recently, a member of parliament said that the Supreme Leader told him that if the leaders of the Green movement faced judgement in a court, because of their massive crime, the verdict would be tough. Why is the Islamic Republic of Iran so reluctant to be transparent about this case?”

Mohammad Taghi Karoubi: “Since the beginning, the regime’s behaviour toward the leaders of the protest movement has been unclear. Part of that behaviour lay with unofficial, shadowy plainclothes forces under regime control. According to international law, the state is in charge of what these groups do. Their methods included attacking my father at home, setting fire to the door of the house and throwing a percussion grenade inside. The regime had its trusted groups do these jobs — unofficially — while at the same time working to avoid any official confrontation between the state and Green movement leaders. So far, no authority has taken responsibility for the house arrest of these leaders, within the framework of current laws. However, some officials have said indirectly that this case is not under their control — such as the top commander of the police and the head of the judiciary. Also, recently, the Supreme Leader clearly expressed that this specific case of house arrest is in his hands. That was not news to us, but exposing this issue publicly has taken us to a new level.”

euronews: “Your father has insisted that he is ready to appear in any court to answer accusations made against him, but the Supreme Leader has said his crime is massive, even though he said the state has treated Mr Karoubi and two other political figures with kindness so far. Do you think the Supreme Leader has made his decision without bothering with a trial?”

Karoubi: “The constitution applies the principle of the presumption of innocence, until a court passes a verdict on the accused. My father has been aware of conditions in the country. Since the beginning of his house arrest, he has declared several times that he is ready to be judged in an open, public trial — as provided for in article 168 of the constitution — his only condition being that he must be allowed to speak to the people. The regime so far has refused to do this. It has not followed judicial procedure. The Supreme Leader said the Green movement leaders are guilty, and yet the crime must be presented in court. Only then, if a guilty verdict is delivered, may punishment be determined. Yet the Supreme Leader has already imposed punishment. Even now, years later, he believes that the regime has been kind to them. It all shows that the handling of the case has not been left up to the judiciary. It shows the judiciary is not independent where the cases of these leaders are concerned. This is because the leaders of the opposition movement have the power to influence the people of Iran.”

euronews: “Last year, following the presidential election which brought in a more moderate government, people went into the streets happily, and once again we heard the names of the leaders of the Green movement in people’s slogans. What does the regime achieve by maintaining this house arrest?”

Karoubi: “After arresting the Green movement’s leaders, the regime tried to use propaganda, the national media and other facilities to make Iranians think negatively about them. They made many allegations against them while giving them no window to defend themselves; student activists and political activists were in prison. The huge historical mistake of the regime was to try to teach society to be negative about these leaders, through state media propaganda. But the last election showed that this vision did not come about. Today, not only has public sensitivity towards the Green movement leaders increased, but their popularity is growing constantly.”

euronews: “About your father’s house arrest conditions, he has moved from place to place. First, he was held at his own home and then he was transferred to a safe house belonging to the intelligence services. Today, he is back in his own home. What purpose did all that serve? It wasn’t done with Mr Mosavi and Ms Rahnavard.”

Karoubi: “My father was held at home, then after several months he was transferred to one of buildings of the intelligence ministry. Our family think it was to put more pressure on him. He held on for two and a half years in a small apartment, with the most basic faciliti