The comment from the Israeli journalist was instructive. We had been seeking his help with a film about the 1982 massacre at Sabra and Shatila in Lebanon and the role of Israel's Prime Minister, Ariel Sharon. "I am not going to do anything that gives the Palestinians any ammunition," he replied. There was no point in arguing. He was emphatic.
An Israeli friend put it down to the current political climate. "Because it is like we are in a war at the moment. You have people carrying out suicide bomb attacks against us. And it involves all of us and it just isn't the time to help anyone to attack your Prime Minister. The Prime Minister is the representative of the state of Israel and when you attack him at this time you are attacking the state. That is how people see it."
Another man with a lot of knowledge on the subject told us he wouldn't help because we weren't investigating the PLO as well. (For the record Yasser Arafat has been the subject of a hard-hitting BBC investigation which accused him of allowing corruption, abuse of free speech and torture.) As for claims by some Israelis that by investigating the issue of war crimes at Sabra and Shatila Panorama is guilty of pro-Palestinian bias, I have nothing but contempt.
Lobbies on both sides of the Middle East engage in a propaganda war. That is their business. At Panorama we are simply being true to a basic principle: it is a duty of journalists to question the actions and record of those who wield power. Ironically the Prime Minister's spokesman, Raanan Gissin, gave us an interview in which he was clearly comfortable addressing Mr Sharon's role in the events of 1982.
Contrary to statements by some Israeli officials, Mr Gissin was fully aware of the subject when he gave the interview; he answered questions about Mr Sharon and war crimes very directly and robustly and when the interview was over he left us on friendly terms. In fact some days later his officials provided us with a letter to help us transit easily through Ben Gurion airport with our tapes.
I read yesterday that an Israeli official had queried why the BBC was "focusing on old news". I would reply simply by saying that the investigation of human rights abuses and the notion of accountability for such abuses is recognised by all civilised states as a fundamental moral and legal obligation.
It was a point recognised by tens of thousands of Israelis when they demonstrated about Sabra and Shatila in 1982. About 400,000 Israelis took to the streets to protest against the massacre in what was believed to have been the biggest demonstration in the history of the state. This was precisely because the people of Israel recognised the scale of what had happened at Sabra and Shatila. When Shimon Peres now Mr Sharon's partner in government addressed the mass rally he said to the world: "Israel is different. It lives by its conscience not just by its sword." And Israel was different.
Unlike any other country in the Middle East it instituted a judicial inquiry. (There was no such inquiry when the late President Assad of Syria ordered the destruction of the town of Hama with thousands of deaths in February 1982).The Kahan Commission's report led to Mr Sharon losing his job as Minister of Defence. And if the man whom Israel's own commission of inquiry found "indirectly responsible" for the massacre is nearly 20 years later elected Prime Minister is it not reasonable to question what he really knew and did and whether his actions and omissions amount to war crimes?
This is more particularly the case in an international environment where the prosecution of war crimes has become one of the issues through we try to define the nature of the world we want to live in. As I said earlier, one of the most fundamental precepts of democracy is the restraint placed on the power of leaders. The greater the power the greater the need for rules and restraints. In the field of international conflict we attempt to restrain or modify the behaviour of leaders and commanders through the Geneva Conventions and the law of war. With questions now being asked in France over the behaviour of its generals in Algeria, a former US presidential candidate forced to explain his actions in the Vietnam war, not to mention the case of General Pinochet and the progress towards the establishment of an International Criminal Court, the debate over war crimes has never been more relevant.
I don't doubt that many supporters of Israel would regard an investigation of Mr Sharon's past as an attack on the state of Israel. It is nothing of the sort. It its very simply a factual investigation of a war crime in which the man elected Prime Minister of Israel was found to have "indirect responsibility".
I have investigated war crimes and human rights abuses in every continent and I have never yet been given a welcome by the people being investigated. Nor do I expect any thanks from the people who were "directly" and "indirectly" responsible for the slaughter at Sabra and Shatila or from their political supporters. The job of a reporter is to deal with the facts. And the facts of Sabra and Shatila are deeply shocking.
I spent four months trawling over the details of the slaughter, speaking to witnesses, reading tens of thousands of words and viewing hours of footage. There is a vast video archive of the Lebanon war and abundant written material available: the report of Israel's Kahan Commission, the report of the International Commission, numerous books on Lebanon's civil war and plenty of legal articles and tomes on the laws of war.
I travelled with the Panorama team to Beirut, Israel, the United States and South Africa to interview witnesses and experts and those accused of different degrees of responsibility. In Beirut we confronted the man accused of leading the slaughter. There was in Lebanon a sense of surprise that we would wish to revisit such an event. As one former militia leader said: "For God's sake if you prosecuted for war crimes here we'd all be in jail." Hadn't everybody committed war crimes? Christians killing Palestinians, Palestinians killing Christians who also killed Druze who also killed Christians, not to mention the killings carried out by the Syrians, the Sunni and Shia Muslims.
On the face of it he has a point, but not one I am inclined to accept. The idea that everybody is as guilty as everybody else and therefore you should have no justice at all is a dangerous way of proceeding; it leads us into a kind of moral free-fire zone. There must surely be a question of proportionality and in Lebanon there were killers and there were mass killers: there is a big difference between the young men who found themselves caught up in war and the butchers who personally directed the slaughter of hundreds of women and children in places like Karantina, Damour (where Palestinian guerrillas massacred Christians), Tel a Zatar and Sabra and Shatila.
The idea that what happened at Sabra and Shatila should not be held up to public scrutiny on the grounds of the general beastliness of the Middle East may be seductive to those who killed and to those who are accused of failing in their responsibilities to the murdered civilians. But if the rest of us are seduced by this argument we abandon the most basic principles of democratic accountability. And that way tyranny lives.
Panorama: 'The Accused' is broadcast at 10.15pm tomorrow on BBC1Reuse content