He preached at Westminster Cathedral before travelling to Canterbury for evensong. He will preach in the cathedral there this morning.
Cardinal Martini has a formidable reputation for scholarship. A Jesuit, he speaks 11 languages and is the author of numerous books.
He combines shrewdness, elegance and authority with his learning. 'You realise at once that you are in the presence of a prince of the church,' says one admirer. 'He is sophisticated and very cool. He could easily have been a papal diplomat abroad. He is one of the few men in the Italian church who speaks in ordinary language, but eloquently, to the people.'
The cardinal has demonstrated enough liberalism to have been lionised by Catholic commentators dismayed by the attitudes of the present pontiff. Could he become the next pope, as so many believe?
In some ways he epitomises the generation of churchmen which for so long conferred on Italy's Christian Democrats the aura of holiness that helped to keep it in power, except that in his case he parted company with that self-enriching regime some time before it was fashionable to do so.
He spoke out in 1986, at the height of the boom, when the Socialist prime minister, Bettino Craxi, was proclaiming a 'new Italy' run by himself and his Christian Democrat allies. In a pastoral letter that year, the cardinal called for an end to the 'cycle of degradation' in Italian public life.
Whether such rectitude will help Cardinal Martini to become Pope is open to question. A Vatican saying has it that 'He who enters the conclave as pope leaves a cardinal' - or, as a bookmaker would say, the favourite never wins.
The chief problem for Cardinal Martini is that while he has been in Milan, the politics of the Vatican have changed. It is not just that liberal inquiry and the questioning of doctrine are no longer prized. The College of Cardinals has been transformed, at least 80 of its 100 or so eligible members having been selected by John Paul II. They are cast in his own image of tradition, timeless authority and all the tendencies in Catholicism that remain unembarrassed by relics, prophecies and miracles.
The college traditionally may move in mysterious ways, but few would expect this particular collection of cardinals to choose a liberal.
Cardinal Martini's visit to the Archbishop of Canterbury, with its overtones of ecumenical fellow-feeling, is unlikely to win friends in such quarters. He already has enemies: Opus Dei, a powerful and secretive sect within the church, dislikes him, and he is openly at odds with Communion and Liberation, a right-wing Italian Catholic revival movement.
Then there is the matter of charisma. John Paul II was elected at a turning point in world affairs, and proved to be the man for the hour. For the Vatican, the confrontation with communism had ranked with the early persecutions, the contest with the Holy Roman Emperors, the Reformation and the French Revolution as a great historic test for the church. Thus to preside over the collapse of communism was a triumph of a kind granted to few popes in history.
It will be a very hard act to follow, and many believe that only a vigorous, telegenic evangelist can meet that challenge. Cardinal Martini, the refined biblical scholar, the Piedmontese bourgeois, the thoughtful observer of political complexities is clearly not cut from that clerical cloth. That he is already 67 years old (the Pope is 74) hardly helps his case.
Despite all the rigid certainty of the present pontificate, however, the College of Cardinals, when it eventually meets to choose the next pope, will have to consider one great question not now being addressed: the Catholic Church may thrive in Africa, Asia and Latin America, but it has manifestly lost the battle against materialism and the proliferation of secular beliefs in the Western democracies.
John Paul II does not much care about dissenting, educated Catholics in America or northern Europe. Yet even in Poland the church has found it easier to defy communism than defeat consumerism. Empty churches and declining birth rate in Italy itself speak volumes.
Can the Catholic Church ever reverse such a historic change? It could be argued that the only method is a change of course, and such a change May just favour Cardinal Martini. The Vatican, it used confidently to be said, thinks only in millennia. The cardinal may be reflecting that the next millennium is only six years away.