You served as a judge under apartheid in South Africa. How difficult was it to fulfil that role?
I wouldn't have accepted an appointment if human rights lawyers hadn't already begun to use the courts to establish rights for black South Africans. People like John Didcott, a leading anti-apartheid campaigner who went on the bench in the Natal region and blazed a trail there, encouraged me. There were already decisions knocking holes in the oppressive system.

Did those campaigners invoke international law or rely on domestic law?
International law was relevant, but Roman-Dutch common law was very egalitarian, and the apartheid legislation overlaid it, so there were gaps where the common law came through. Apartheid legislators liked to use benign words in their statutes, hoping the judges would know how to interpret them, so there were large areas where one could interpret the law in a way that was less oppressive. Later I chaired the Commission of Inquiry Regarding Public Violence and Intimidation, which exposed illegal behaviour even under apartheid.

South Africa is still your home. Do you feel the government has lived up to early expectations?
South Africa, for all its problems, has been a tremendous success. But expectations were unrealistically high. It will take decades, generations, to overcome the heritage of 350 years of racial oppression. It's going in a good direction.

You were prosecutor at the Yugoslav Tribunal. Was it an example of victors' justice?
Nuremberg was victors' justice, but The Hague certainly wasn't. It was anything but. It was an international court, and none of the judges involved had an interest.

There were accusations that a quota from each side was prosecuted to prove impartiality.
There was definitely pressure in that direction, but I did not succumb to it. In my book, being even-handed means treating similar crimes
similarly. So if - on a scale of one to ten, with ten the most serious - we were prosecuting crimes by the Serbs rated ten, it was not appropriate to go after ones or twos committed by Bosniaks.

How important was the tribunal?
It was hugely significant: the first truly international, as opposed to multinational, court. It was part of a very welcome development in international law, which has been progressively removing impunity from war criminals.

Were the Yugoslav and the Rwanda tribunals a flash in the pan?
Not at all. They gave rise to the International Criminal Court, supported by 110 nations - admittedly not some of the most powerful, such as Russia and the US, but that will change. The movement is in one direction. Just recently, for the first time in eight years, the US was an observer at the meetings of states party to the ICC.

There are still furious debates about the Kosovo intervention. What's your assessment?
I chaired the International Commission on Kosovo. We came to a unanimous conclusion -
I suppose an oxymoron - that the Nato intervention was illegal but legitimate. Russia tried to get the Security Council to condemn the Ko­sovo intervention but lost by 12 votes to three. It was an after-the-fact acceptance of what happened. That led to the Canadian inquiry, which developed into the "Responsibility to Protect" doctrine, which has in turn become soft law.

Some who criticised your support for Nato now cheer the Gaza report. What about accusations that it was biased against Israel?
The original mandate was biased, but the president of the Human Rights Council agreed with me to change it. As with Rwanda and Yugosla­via, we investigated all sides.

Were you apprehensive taking it on?
Of course! The Middle East is not the easiest part of the world, but I assumed, perhaps naively, that because of the even-handed mandate, Israel would co-operate. Obviously I was really saddened when they refused.

You've been described as a friend of Israel, a Zionist. Is that accurate?
I'm certainly a friend of Israel. I don't mind being called a Zionist; it depends on the definition.
Perhaps that's why you weren't criticised to begin with. Then the floodgates opened . . .
There has definitely been a consistent effort to attack the messenger rather than read the report. Clearly, personal attacks have been unpleasant for me, and unpleasant for my family.

Where do you see the Gaza debate going now?
I hate prophesying. I really do not know how it will go, but the report seems to have gained its own momentum.

How has the new era of accountability for war crimes changed the landscape?
Impunity, generally speaking, has come to an end - I don't think there's any person today accused of committing international crimes who can feel happy travelling. That in itself, if not a complete success, must act as a deterrent.