His appearance is jovial and his demeanour reflects his occupations. He is precise – he is a barrister after all – and measured, because he teaches undergraduates. But his recent election as one of the 15 permanent judges at the UN’s International Court of Justice (ICJ) raised eyebrows – Northern Ireland MP Mark Durkan tabled a motion in the House of Commons that his appointment should not be supported by the government. Canadian MP Dawn Black is reported to have labelled him ‘a discredited, right-wing expert’.

On the face of it, it is hard to see what exactly has got everybody so excited. His credentials for the job are impeccable: an academic for 31 years as an expert in international law; a successful parallel career at the bar at Essex Court chambers in London, taking silk a decade ago; and an arbitration panel member. To earn his seat at the ICJ, he underwent a rigorous election process, involving face-to-face meetings with a representative of almost every member country of the UN (there are almost 200 of them) and he received a unanimous vote from the UN Security Council. So what is the problem?

The problem is that, as a barrister, he has acted for the government in a number of very high-profile cases and advised it on some of the key issues of recent times. Most importantly of all, in March 2003 he was asked to assist the government in the preparation of legal documents in relation to Britain’s invasion of Iraq. His involvement has been distorted by the press, but it is a reflection of the passion and polarisation of views which the war in Iraq has created that the press gave him the label ‘the War QC’.

Greenwood’s office at the London School of Economics, his academic home since 1996, is being packed up in preparation for an upcoming relocation to The Hague to begin his nine-year term at the ICJ. So, we meet in the Waldorf Hotel a stone’s throw away. The hotel patisserie’s wood-panelled interior is full of semi-serious meetings and polite exchanges. Greenwood is punctilious, and comes dressed as a barrister, not as an academic. He appears calm about his new life at The Hague, a change that will mean the end of his two successful careers here in the UK.

For an international lawyer, a judicial position at an international court is the logical progression. However, unlike his national counterparts here, Greenwood has been elected rather than appointed. Each candidate for the ICJ must secure an absolute majority of votes within the UN Security Council and the General Assembly. So, Greenwood has been on the campaign trail.

Electing judges is still anathema to the judicial process in the UK. Indeed, the Economist recently reported that the electoral process for international tribunals means ‘there is no guarantee that… ballots will produce individuals who are qualified or honest. Decisions affecting millions of lives can be taken by questionable people’. It was not, of course, referring to Greenwood, but the judge-elect agrees that elections are ‘counter-intuitive for an English lawyer’. He says, however, that it is the only way to do it at the UN. ‘It is not easy to see how else it could be done. If you had an appointments commission [as we now do here], you’d then just have to work out how you elected that commission!’

Though it is the legal arm of the UN, the ICJ is not particularly well known in the UK. It is often confused with the European Court of Justice or even the new International Criminal Court, also at The Hague. But its low profile is also attributed to the fact that the court is quite different from an English one, as Greenwood knows, having appeared before it in its Great Hall as an advocate for a number of different governments. Greenwood is in a minority among the judges for being an advocate – most of them are civil servants, ambassadors and academics. This court has none of the interaction of an English courtroom: judges do not interrupt or ask questions, a result of the bilingual nature of the court, which makes spontaneous questions a practical difficulty. But, Greenwood says, the lack of interest in it from the British public is not replicated elsewhere in Europe. ‘It is peculiar to this country and a few like it that the ICJ is rather neglected. When I did a maritime boundary dispute as counsel for Honduras against Nicaragua, the press in both countries covered the dispute on the front page every day of the hearing. But cases such as Georgia and Russia, or advisory proceedings on Kosovo, will get greater attention [in the UK].’

If the British public is uninterested, the US is scathing. One infamous critic there is Eric Posner, a professor of law at the University of Chicago, who criticises what he sees as the ICJ’s anti-American stance and also the fact it is sometimes called ‘the world’s court’. As he wrote in the Wall Street Journal a few years ago, ‘such an institution cannot exist, because the world is not an organic political community’.

Others in the US and elsewhere complain of the court’s lack of punch, but Greenwood calmly rebuts this. ‘The court has hardly ever given a judgment in a case between states that those states haven’t observed,’ he says, with no hint of defensiveness. Certainly, the ICJ is summoned each time there is an international crisis.

On the day that Greenwood and I meet, the Israeli military action in Gaza is dominating the headlines. Israel is being accused of war crimes and there are calls for the ICJ to step in. In 2004, the ICJ had given an advisory (non-binding) opinion on the security wall separating most of the West Bank from areas inside Israel, so it had some history of getting involved in the region. Greenwood declines to comment on the specifics, but explains what the court could do. ‘The ICJ has no criminal jurisdiction, no individual can be prosecuted before it. But there could be a case between two states about allegations of war crimes, and that has happened several times. [The court] might decide that one state had violated the Geneva Conventions, let’s say, because of war crimes committed by its armed forces, or it might hold that one state had violated its obligations by failing to prosecute somebody for war crimes or failing to extradite them.’

Greenwood gives explanations as we discuss these sensitive issues, not sermons. He certainly doesn’t try to persuade me of the benefits of the ICJ. Again I find myself wondering how this man could be so controversial. Even his views on the strengths and weaknesses of international law are rational and balanced – even if one doesn’t agree with him. We discuss a lecture he has just given entitled ‘Can international law change the world?’, so I ask him the same question, to which he replies: ‘International law by itself will not change the world, any more than English law by itself can change our society here. I sometimes think that it is a fallacy that passing an act of parliament or adopting a treaty is somehow to bring about the radical change itself. The change lies in enforcing it, securing compliance with it, and there you have a very complex relationship between law, changing attitudes, education and enforcement. You won’t stop climate change by signing a treaty [but] you might arrest the process of climate change or even turn the process back if you have the right treaty, approached and applied in the right way.’ Greenwood’s position is – if I can put it this way – that of a hopeful realist.

The waitress brings us both some water. A slice of lemon sits on top of the ice in Greenwood’s tall glass, which he extricates with care and precision. Clearly, he does not like lemon. I choose this moment to mention the Iraq war and those who have objected to his nomination to the ICJ on the basis of his relationship – as his critics see it – with the British government and the decision to go to war in Iraq. He is sanguine in reply. ‘People disagreed about Iraq, but it was hardly raised with me when I was meeting with diplomats in the UN. I think I was asked twice out of the 170 or so interviews I did. Part of the problem is people have ideas about what happened which don’t reflect reality.’

Greenwood explains this further by saying that ‘the view I took about whether the use of force in Iraq was lawful was well known, but I wasn’t involved in advising on whether military action would be lawful’. Greenwood draws a line between the before and after. He says he was asked to give his opinion on the legal consequences of a war in Iraq. ‘I didn’t advise on the legality of use of force at all. I did advise on various issues that arose afterwards and of course I took part in various cases that arose afterwards.’

This passing reference to ‘various cases’ is critical, however, to the perception that people have of him: they include cases arising out of internments at Guantanamo Bay, in which he acted for the government against those who were arguing that Britain should appeal to the US to allow British detainees to return home. He also acted for the government in the Bankovic case, where he opposed arguments that NATO’s bombing in Serbia was an infringement of human rights. There is a theme here, I suggest, but Greenwood bats that aside. ‘People do tend to associate a barrister with the high-profile cases he has done. If you go through the different cases I have appeared in, if I were genuinely a "cause" lawyer rather than somebody who was acting for a client, you’d get a very odd picture of the things that I have done. I also acted against the British government, for instance, in the Pinochet case [where he argued against the immunity of the former Chilean dictator]. I act for my client within the rules of professional ethics. My own beliefs are an entirely different matter.’

Although I can see the conundrum that the barrister-client relationship raises, Greenwood has not shied away from discussing key issues of international law in public. He argued in the press that Saddam Hussein should be tried by the Iraqis, not an international tribunal – an unpopular stance among many international lawyers. There is beyond the barrister, therefore, a man with opinions, someone who likes to make up his own mind – even if his conclusions are unpopular. This is exactly the skill he must now employ as a judge.

Greenwood’s new post is a huge honour. He will have ambassadorial status and so be referred to as ‘His Excellency’. Britain should now probably start to take more of an interest in the ICJ and its newly appointed judge – it seems he is not a man to sit quietly.

Born in 1955, Chris Greenwood was a fellow of Magdalene College, Cambridge from the age of 23 in 1978 until 1996. He then took up a post at the LSE as Professor of International Law, which he held until his appointment to the International Court of Justice. He was called to the bar in 1978, joining Essex Court Chambers, and took silk in 1999. This year he received a knighthood.

Polly Botsford is a freelance journalist