IF TARIQ AZIZ WAS expecting an easy ride last week when he had a private audience with the Pope, he must have had a bit of a shock. A Chaldean Catholic, the Iraqi deputy prime minister was given half an hour with the pontiff rather than the scheduled 15 minutes. The extra time was not for pleasantries, or for a discussion of the finer points of theology — it was to enable the Pope to give Aziz (who until then had been fêted in Italy as a celebrity) a stern lecture on exactly why and how Iraq should comply with United Nations resolutions to avoid war.

Tony Blair can take comfort from the fact that not all papal audiences consist of hard talk. Many are ceremonial: the Pope receives delegations almost every morning and a steady stream of world leaders passes through the Vatican’s marble halls. Some are making courtesy calls on an historic, charismatic figure who for 25 years has remained a fixed point of reference in a changing world. If Cherie Blair accompanies her husband to the Vatican on Saturday the occasion will have a different flavour, partly because she is Catholic while he is Anglican, and partly because it makes the visit more informal.

But Mr Blair and the Pope will almost certainly begin with a face to face encounter on their own. “Cherie will be taken off by a Vatican official to be shown the Raphael Rooms or the Sistine Chapel,” one insider says, especially if the meeting with the Pope is followed by another — as is often the case — with Cardinal Angelo Sodano, the Secretary of State (in effect, the Pope’s Prime Minister). The Vatican is not just the focus of Catholic faith, it is a global power, with clear views on political and moral issues and a worldwide diplomatic machine.

Papal audiences come in two forms — the general ones every Wednesday, when several thousand pilgrims “meet” the Pope in the sense of sitting in the same hall with him: and private audiences. For the latter, protocol is strict: accompanied by the American Monsignor James Harvey, head of the papal household, visitors enter not the Paul VI audience hall, where the mass receptions are held, but the Apostolic Palace itself, the holy of holies, reached via the St Damasus courtyard, with the Swiss Guard forming a guard of honour.

The Pope, dressed in white with a white zucchetto (skull cap), greets his guests in his private library on the second floor. Sometimes he sits in a chair with his chief guests on either side of him and a large painting of Christ Resurrected behind him; sometimes — usually when he wants to give the occasion greater formality — he sits at his desk, bare apart from a leather blotter on which lies the text of his prepared remarks, with his guest (or guests) facing him on the other side of the table.

The desk will also have on it any gifts that he intends to give the visitors, and the gifts they have brought for him. Before the meeting, those about to meet the Pope are tactfully reminded by the Vatican’s protocol officers of the rules: Catholics usually bend to kiss the Pope’s ring, while non-Catholics (such as Mr Blair) simply incline their heads and shake his hand.

Women are expected to wear black, their hair covered by a black mantilla. The Pope, a noted polyglot, usually greets his visitors in their native language; though frail and ill at 82, he is mentally sharp as ever and still speaks fluent if heavily accented English. But then Vatican staff step in to help. In the case of English-speaking visitors assistance is often provided by Monsignor Bryan Chestle, a long serving British official in the Secretary of State’s office, as well as Monsignor Harvey. Hovering at the Pope’s elbow, as he has for decades, is Bishop Stanislaw Dziwisz, the Pope’s faithful Polish secretary, regarded by many as the keeper of the Pope’s door and the real “power behind the throne”. He has been privy to almost all of the Pope’s conversations with the world’s men and women of power in the past 25 years.

Many of the encounters have had historic consequences. When Mikhail Gorbachev sat opposite the Pope in December 1989 (the two men spoke alone in Russian before being joined by officials) he was overwhelmed not only by the Pope’s force of personality but also by his insistence that it would prove impossible to reform the Soviet system without destroying it (a prophetic remark) and (no less prophetic) that Russia could not regain its “human dignity” without abandoning atheism and returning to God.

When George Bush met the Pope after the G8 summit in Genoa in June 2001, he was given a stern dressing down over genetics and embryo stem-cell research as well as the impact of globalisation on trade and Third World poverty. Invariably it is the world leaders who want to see the Pope rather than the other way round — yet invariably they end up listening meekly to a lecture on where they are going wrong and what they should do about it.

In this case too, it seems, Mr Blair has been seeking an audience with the Pope for some months. Perhaps he wants to try to persuade the Pope that war on Iraq would be “just”; or perhaps, as a Christian, he wants to hear for himself why the Pope believes it is not. Either way, he had better brush up on his Aquinas.

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