A papal aide who compared Britain to a ‘Third World Country’ is being called on to apologise as the pope flies in for his controversial visit.

Cardinal Walter Kasper told German magazine Focus that someone landing at Heathrow airport might think they were in a ‘Third World country’ as there are such a variety of multicultural faces there.

Asked whether he thought Christians were discriminated against, the 77-year-old added: “Yes. Above all, an aggressive new atheism has spread through Britain.”

The cardinal has pulled out of joining the pope on his visit to Britain, reportedly for health reasons. However, he is being called on to apologise for the ‘Third world Britain’ remarks.

Cardinal Keith O’Brien, leader of the Catholic Church in Scotland told BBC Radio Scotland: “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.”

The comments will add to the controversy over the pope’s visit which centres around his attitude to homosexuality, contraception and the cover-up of the child abuse scandal within the church.

Related: Pregnant nun ice cream ad banned

Your guide to the pope’s visit