With the news late on 1 February that Pope John Paul II had been admitted to the Policlinico Gemelli in Rome with breathing complications, the city once again woke up to the realisation that it is home to one of the worlds most important people. Once again all eyes turned to the eternal city, as news of the pontiffs illness circulated the globe.

A change in the state of the health of the 84-year-old pope, who has been ailing with Parkinsons disease for many years, was enough to send journalists scurrying from all over to watch as close to his bedside as possible.

The front line, so to speak, was the Gemelli hospital, about a 20-minute traffic-packed drive from the Vatican. Here the movement of doctors and nurses in and out of the 3,000-bed concrete-and-glass structure was one of the clues to the real state of the popes health. The next was the coming and going of cars with SV plates bearing notables from the Holy See. Then there were the regular health bulletins, in their laconic language, which sent journalists flying to their medical dictionaries. The official last resort was the Vatican newsroom, presided over by the ever-faithful, and always secretive Joaquin Navarro-Valls, the man who was still denying that the pope had Parkinsons disease long after almost everyone with an ear close to the Vatican was talking about it openly.

The city has seen 263 popes come and go, from St Peter, the first, to the ill-fated John Paul I, this popes immediate predecessor, who reigned for only a few weeks in 1978 before he died as unexpectedly as he had been elected. But the end of the present pontiffs reign, when it comes, just as the pontificate itself, will be like no other.

If John Paul II were to die in hospital, that would be a first in itself. Popes have died outside the Vatican but none of them has died in a public hospital. That the pope was being treated as an ordinary citizen, albeit a very special one, was itself symbolic of his whole pontificate that of an extraordinary man with a very special common touch, in tune with ordinary people across the world, be they Christians or not.

His return to the Gemelli, where he has been treated for various illnesses since his first dramatic visit there after the attempt on his life in 1981, was nothing new in itself. But a long-drawn-out illness there, or his demise, would change many things. It would move the centre of his dwindling pontificate out from behind the Vatican walls, where all news is tightly controlled, managed and filtered by his faithful staff. The very fact of being in a public hospital would mean that there would be much less mystery about the progress of this popes health good or bad than there has been about that of his predecessors, the details of whose declining moments have often been shrouded in mystery.

The fact of being in a busy hospital makes things, per se, more public. Even if the doctors, specialists and nurses will be ever-careful about what they say and how they say it, even if journalists are kept from entering the hospital, ordinary patients and the coming-and-goings of their relations and friends cannot be stopped. In addition, the journalists sent off to hospital-watch the papal story were not the usual Vatican press corps, those experts on all pontifical matters, but a much less homogeneous and probably more aggressive lot, on the hunt for a scoop.

And while the pope received top medical treatment and supervision, something that has not always been available to his predecessors closeted in their papal apartments, the city and the world once again dusted off the procedures for what happens when

The when is divided into three distinct parts: the declaration of death, mourning and the burial of the present pontiff; the conclave of cardinals to elect the person to succeed him; the presentation and the coronation of the next man to sit on the throne of St Peter because man it must be, although he doesnt necessarily have to be a cardinal.

Between the death of this pontiff and the election of the next, the person in charge of most of the proceedings is the chamberlain or camerlengo, at present Cardinal Eduardo Martinez Somalo, who has been in the post since 1993. He was born in Spain in 1927. However it is not the chamberlain who convenes the conclave but the dean of the college of cardinals. At present this position is held by Cardinal Joseph Ratzinger, born in Germany in 1927, the powerful prefect for the congregation for the doctrine of the faith.

The time between the declaration of death and the opening of the conclave can take from 15 to 20 days. The conclave lasts as long as it takes to arrive at two thirds plus one of the votes of the eligible cardinals those under the age of 80. Under the rules for the election laid down by the pope in February 1996 in Universi Dominici Gregis the maximum number of cardinals who can vote in the conclave is 120.

If such a vote is not achieved within 12 or 13 days the cardinals may agree to choose the next pope by an absolute majority, half plus one of the votes. Or they may vote for the two people who have obtained the most votes in the preceding ballot. During the conclave all cardinals have to respect complete secrecy about the events within the Sistine Chapel. It is here that they meet to say Mass, pray and cast their ballots, two each morning and two each afternoon, until the new pope is chosen. The papers are burnt after each vote and if black smoke emerges from the chimney, which is visible in St Peters Square, it means that no agreement has been reached. It is the appearance of white smoke that will announce the cardinals have picked the new pontiff.

When the time comes, there will be many new aspects of the election. One of these is that the cardinals will no longer be secluded in the uncomfortable quarters near the Sistine Chapel in the heart of the Vatican City. They will be housed in new and very comfortable facilities on the left of St Peters basilica, near the outer walls, on the opposite side of the square to the chapel. The comings and goings of the cardinals will no longer be hidden from public eye as they move to and from the chapel to vote. This time the traditional crowds that gather in St Peters Square between the death of one pope and the election of the next will be there not only to watch the smoke but also to scrutinise the comings and goings of the princes of the Church.

Whatever happens from now on will be a combination of the old traditions and new, more modern procedures. There will be many unexpected moments in store, not least whether the choice of the next head of the Roman Catholic church will signal a return to its old and well-tried Italian roots, or whether the ship of state will head out once again into unknown seas and pick a man from a new continent to step into the shoes of St Peter.