It might seem as if the Vatican has no moral authority left to lose, but with his description of Britain as a "third world country", Cardinal Walter Kasper has done his best.
In an interview with the German news magazine Focus, Kasper declared:
[Britain is] a secular and pluralist country. Sometimes, when you land at Heathrow, you think you have entered a third world country.
Some bloggers  have interpreted Kasper's comments as an attack on the quality of Heathrow Airport. But they, along with much of the mainstream media, have obviously missed the "clarification" issued by the Vatican.
According to the Pope's spokesman, Father Federico Lombardi, Kasper's comments actually referred to Britain's multi-ethnic composition. Is Kasper really suggesting that ethnic minorities have no place in a developed country like Britain?
Apparently so. One can only assume that the multi-ethnic nature of travellers (and staff) at Heathrow offended the cardinal's separatist sensibilities.
Kasper, who has withdrawn from the papal visit, has already come under pressure to apologise. Cardinal O'Brien, leader of the Roman Catholic Church in Scotland, said:
That was unfortunate, and each and every person's aides sometimes do make awkward, difficult remarks. Sometimes we make awkward, difficult remarks ourselves. And simply, if we do that sort of thing, we apologise for it, and I'm sure Cardinal Kasper will apologise for any intemperate remarks which he made some time ago.
But these are weasel words compared to the scale of Kasper's offence. If the Vatican, many of whose followers live in the "third world", wishes to salvage some dignity, it could begin by ordering Kasper to apologise for his slur on the UK and its population.