Presidents will rub shoulders with kings and queens at the Pope's funeral in a diplomatic nightmare that will accompany one of the biggest ever gatherings of world leaders in modern times, as well as one of the largest gatherings of pilgrims, who are expected to number up to four million.

Presidents will rub shoulders with kings and queens at the Pope's funeral in a diplomatic nightmare that will accompany one of the biggest ever gatherings of world leaders in modern times, as well as one of the largest gatherings of pilgrims, who are expected to number up to four million.

US President George Bush will be accompanied by his wife Laura and a "small delegation" of American officials for the funeral in Vatican City.

President Bush said yesterday it was a "great honour, on behalf of our country, to express our gratitude to the Almighty for such a man. And of course we look forward to the majesty of celebrating such a significant human life."

Edward Kennedy is among other American politicians certain to arrive, while there is speculation in Rome that George Bush Sr and Bill Clinton will also show up.

Prince Charles delayed his own marriage by a day in order to accompany Tony Blair and the Archbishop of Canterbury, Dr Rowan Williams, to Rome.

Pope John Paul II's worldwide popularity and the political importance of Catholics in so many countries guarantees a curious assortment in Rome of the good and the great. Kofi Annan will be there. King Abdullah of Jordan has also confirmed.

Italian newspapers were abuzz with the possibility that the Pope improbable friend Fidel Castro might make it. Despite the fact that Castro declared a three-day period of national mourning for the pope, this now appears unlikely, though he will certainly send an important representative.

President Aleksander Kwasniewski, of Poland, is sure to attend, along with Lech Walesa, the trade unionist whose Solidarity movement was supported by the Pope's firm stand against Poland's communist authorities.

Spanish Prime Minister Jose Luis Rodriguez Zapatero will come to Rome, though he has few friends in the Curia following his bruising assertion of the secular nature of the Spanish state and his approval of gay marriages. King Juan Carlos and Queen Sofia will accompany Zapatero.

Ireland is sending President Mary McAleese and Prime Minister Bertie Ahern, who faced questions yesterday after he refused to declare Friday a national holiday in the staunchly Roman Catholic republic.

Italy is also counting on the appearance of Nelson Mandela, and Israel's foreign minister Silvan Shalom, in recognition of the late pope's attempts to build trust and amity between Christianity and Judaism. President Jacques Chirac of France will also be there. Others include President Vincente Fox, of Mexico, and triumphant Ukrainian president Victor Yushchenko, President Horst Koehler and Chancellor Gerhard Schroeder of Germany will also attend.

Throw in such religious figures as Russian Orthodox patriarch Alessio II, Sister Nirmala, leader of Mother Teresa's Missionaries of Charity and high profile Muslim delegations and the potential for political fireworks appears to be great. The protocol challenge will be complex, although it is a challenge for which the Vatican has had ample time to prepare.

It is expected that at least some of the world leaders will take advantage of the event to hold one-on-one meetings with other leaders while they are gathered in Rome.

President Bush met the Pope three times during his presidency, and on the last occasion the president was famously scolded for his attachment to aggression as a means of solving problems. The Pope was a formidable opponent of the war in Iraq.

Nonetheless, President Bush said yesterday that he was looking forward to attending Pope John Paul II's funeral.

VIP MOURNERS

BRITAIN: Prince Charles, Prime Minister Tony Blair

UNITED STATES: President George Bush and Laura Bush

POLAND: President Aleksander Kwasniewski, Prime Minister Marek Belka, Lech Walesa

AUSTRIA: President Heinz Fischer

FRANCE: President Jacques Chirac and Bernadette Chirac

GERMANY: President Horst Köhler, Chancellor Gerhard Schröder

HUNGARY: President Ferenc Madl, Prime Minister Ferenc Gyurcsany

IRELAND: President Mary McAleese, Taoiseach Bertie Ahern

ITALY: President Carlo Ciampi, Prime Minister Silvio Berlusconi

LEBANON: President Emile Lahoud

PORTUGAL: President Jorge Sampaio, President of the European Commission, Jose Manuel Barroso

RUSSIA: Prime Minister Mikhail Fradkov, Metropolitan Kirill of the Orthodox Church

SPAIN: King Juan Carlos and Queen Sofia, Prime Minister Jose Luis Zapatero

SYRIA: President Bashar Assad