On the plane to Edinburgh, Benedict himself commented that people had warned him before he went to France or the Czech Republic, and the worst did not materialize. But then he explained that how he is received is not really the relevant criterion.

“One might say that a Church which seeks above all to be attractive would already be on the wrong path, because the Church does not work for itself, does not work to increase its numbers so as to have more power,” he told journalists who were travelling with him. “The Church is at the service of Another; it does not serve itself, seeking to be a strong body, but it strives to make the Gospel of Jesus Christ accessible, the great truths, the great powers of love and of reconciliation that come always from the presence of Jesus Christ. In this sense, the Church does not seek to be attractive, but rather to make herself transparent for Jesus Christ.”

Of the many things Benedict said in historic places while in Britain, that was the key to understanding why the Holy Father travels. He does not need the crowds — they come to see him every week in Rome. Benedict himself is rather self-conscious about all the hoopla of a papal visit, and being in front of great crowds is onerous for him. He travels not for his own sake, but so that others may hear the Gospel.

Sometimes it is a matter of proclaiming, and sometimes a matter of reminding. Britain is already a post-Christian country, where the religious leadership has been largely neutered and atheism is rather more chic than Christian piety. Benedict warned that if a culture shaped by Christianity severs itself from its own roots, it will embrace any passing fashion, including destructive ones. The vulgarity of British culture, the viciousness of its secular extremists, the drunken boorishness of its youth — all this is a betrayal of its noble Christian heritage.

“The Christian message has been an integral part of the language, thought and culture of the peoples of these islands for more than a thousand years,” the Holy Father said to the Queen.

Benedict came here to beatify Cardinal John Henry Newman, not only one of the greatest Englishmen ever to live, but a model of all the great virtues of Englishness. All that is now being dismantled and discarded in the name of a secularism that is actively hostile to religious believers, Christians in particular.

Benedict’s first words here reminded me of what Pope John Paul II said on the first day of his historic first pilgrimage to Poland in June 1979. He argued that Poland could not be understood properly with reference to her Catholic faith.

“Therefore Christ cannot be kept out of the history of man in any part of the globe, at any longitude or latitude of geography,” John Paul preached. “The exclusion of Christ from the history of man is an act against man. Without Christ it is impossible to understand the history of Poland, especially the history of the people who have passed or are passing through this land. The history of the nation is above all the history of people. And the history of each person unfolds in Jesus Christ. In Him it becomes the history of salvation.”

Thirty years ago John Paul inveighed against the communists who were trying to rip up the Christian roots of Polish society. Benedict made the same argument here, not against communist state power, but the ideology of radical secularism, promoted by both society and state. And Benedict made his critique more pointed by repeated references to the Nazi regime — which itself set out to destroy the Christian presence in German society.

Was it possible, this German Pope asked his British audience, that the Christian moral foundation that permitted Britain to defeat Nazi Germany at great cost would be set aside today as something dangerous? And if so, what would replace it?

There is no replacement for the Gospel, Benedict came here to argue. He returned home having done so. The true measure of success will be whether a significant number of people listened to him.