Cardinal Walter Kasper's sudden diplomatic illness tells us almost as much about the Vatican's real plans as his undiplomatic remarks to a German news magazine. In an interview with Focus, he said that "an aggressive new atheism has spread through Britain. If, for example, you wear a cross on British Airways, you are discriminated against."

Kasper is normally one of the Vatican's more diplomatic and emollient figures. He spent years negotiating with the Church of England. He was the man the Archbishop of Canterbury, Rowan Williams, rang up in a rage when plans emerged for a mass defection to the Roman Catholic Church of Anglican opponents to women priests.

Yet he was also the man who in 2008 urged the Anglican communion to take a stand against homosexuality. And his remarks fit into a conservative view of Britain, one which would have appealed to John Henry Newman in his conservative moods. And it is Newman who the pope has come here to beatify.

Britain today, said Kasper, is "a secularised [translation corrected] and pluralist country. Sometimes, when you land at Heathrow, you think you have entered a third world country."

The standard liberal remedies for the church's decline hold no attraction for the cardinal. "Look at the Protestant churches," he said: "They have married priests and women priests, too. Are they doing better? The Church of England has also taken on terrible problems with these developments. I wouldn't wish those problems on my church."

This is not only stupefyingly tactless, and wrong (the Church of England has 600 priests in training, half of them women; the Roman Catholic church here has 39), it is also bizarre, in view of the pope's initiative last year to welcome married Anglican clergy, if they are opposed to women priests.

The Church of England, Kasper believes, has been brought to the point of schism and collapse by compromise with the spirit of the age. He says: "There is a crisis of values and direction in western society which has its roots in the Enlightenment, and was given added impetus by the radical movements of the 60s. And because the churches live in this society, their faith is weakened."

This view will horrify many English Catholics. For the liberals in the English church, the reforming Second Vatican Council of the 60s opened the church to learning from the outside world, and the last two popes have attempted to drag down again the iron shutters which once kept the church distinct. But to Pope Benedict and his circle, the council showed it had learned all the necessary lessons of the 500 years since the Reformation. Now it is time once more for the world to learn from the church.

This view has a certain lunatic consistency. By blaming almost everything wrong with the church on liberalism and acoustic guitars, it pushes into the future any consideration of whether things will get better when those have been extirpated. It sets up the Catholic church as defender of European identity against Islam, and against secularism. The restoration of the Latin mass is also, partly, an attempt to restore Europe to its Christian roots by establishing a living ritual that appears to go back centuries.

All this, I think, is what the Vatican really believes it is up to, and Kasper just blurted it out. What his sudden mysterious illness adds to the picture is that it is determined that there should be no diplomatic incidents on this trip – and that it still has no clue how to avoid them.