The Iraq inquiry will start hearing evidence in open session on Tuesday, and it will almost certainly lead to fireworks. Let us hope the media cover it properly; five months ago, there was a sharp debate on Iraq in the Commons which the media ignored.

"Anyone with information" has been invited to get in touch, which includes serving officials and military. Some officials resigned because they disagreed with the war, but most stayed on. But there is plenty of evidence, including leaked documents, to show there was strong opposition to the war, and for good reasons. As a retired diplomat myself, I hope my former colleagues will not be shy.

The situation in Iraq is still horrible. More than 400 people died in violent incidents last month; more than 1,400 were wounded. Millions of Iraqis are still displaced, inside Iraq or in Syria, Jordan or elsewhere, with little prospect of their returning home. Water and electricity are limping along, the vital oil industry will take years to rebuild. British troops sent to train the Iraqi security forces were in Kuwait through the summer marking time, while the Iraqi government quibbled about their legal status.

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We've had umpteen Iraq inquiries already, but this one should be different. Its terms of reference are open. Previous inquiries concentrated on the non-existent weapons of mass destruction, the misuse of intelligence to make the case for war, the "dodgy dossier" and so on. But there are plenty of other questions, starting with the big one: was this a war of aggression and therefore a war crime? There were two views about its legality, and the then attorney general seems to have held both of them.

What about the alleged links between Saddam Hussein and al-Qa'ida? – it seems there were no such links. What happened to the civil planning for after the fighting? – according to Clare Short, who was a member of the Cabinet, there "were preparations that were then all junked, because of the hubris and deceit that went into preparing for war". Were the arguments for and against war ever assessed by the FCO, and was formal advice submitted to the then secretary of state, the Cabinet and the prime minister? Here is Clare Short again: "All the Cabinet meetings were little chats: they were never a proper consideration of all the options." Is it true that the Iraq experts invited to No 10 in November 2002 (two of whom also took part in the seminar organised by the inquiry on 5 November) decided not to tell Tony Blair whether they thought an invasion was wise or not because they thought he wouldn't listen? We have heard a lot recently about the freedom of experts to give advice which is unpalatable to the Government, so why the self-censorship?

We need to know more about the exchanges between George Bush and Tony Blair. According to Colin Powell, the then US secretary of state, he and Jack Straw sometimes tried to get Blair to hold Bush back. "Jack and I would get him all pumped up about an issue. And he'd be ready to say, 'Look here, George'. But as soon as he saw the president he would lose all his steam." Can this be true?

When Bush tried to persuade President Chirac to go to war, Bush compared Saddam Hussein with Gog and Magog, obscure legendary figures named in the book of Ezekiel as enemies of the people of Israel. This sounds like a joke, but seems to be true. Chirac was baffled and his staff consulted a professor of theology who spilt the beans. Blair told his Iraq experts that Saddam was "uniquely evil"; the inquiry should ask him whether Bush mentioned Gog and Magog to him, or he to Bush.

The Prime Minister's choice of the members of the committee has been criticised. None is a military man, Sir John Chilcot was a member of the Hutton inquiry and has been closely involved with the security services, Baroness Prashar has no relevant experience, Sir Roderic Lyne was a serving ambassador at the time of the war, and so on.

Rather less attention has been paid to the curious appointment of two historians (which seems a lot, out of a total of five), both strong supporters of Tony Blair and/or the Iraq war. In December 2004 Sir Martin Gilbert, while pointing out that the "war on terror" was not a third world war, wrote that Bush and Blair "may well, with the passage of time and the opening of the archives, join the ranks of Roosevelt and Churchill" – an eccentric opinion that would se em to rule him out as a member of the committee. Sir Lawrence Freedman is the reputed architect of the "Blair doctrine" of humanitarian intervention, which was invoked in Kosovo and Afghanistan as well as Iraq.

Both Gilbert and Freedman are Jewish, and Gilbert at least has a record of active support for Zionism. Such facts are not usually mentioned in the mainstream British and American media, but The Jewish Chronicle and the Israeli media have no such inhibitions, and the Arabic media both in London and in the region are usually not far behind.

All five members have outstanding reputations and records, but it is a pity that, if and when the inquiry is accused of a whitewash, such handy ammunition will be available. Membership should not only be balanced; it should be seen to be balanced.

Tony Blair's responsibility for the Iraq war was a strike against him as a candidate for the role of president of the European Council. Perhaps the launch of the inquiry helped to kill the idea off. No European democratic institution has entertained the idea of electing someone under the shadow of a war crime charge since Kurt Waldheim became President of Austria in 1986.

Oliver Miles is a former British ambassador to Libya

Bush's biblical justification for war: secularhumanism.org/index.php?section=library&page=haught_29_5