The controversial show, which features naked portraits of themselves, plus human excrement and semen, has been condemned as "an assault upon decency and morality".

Rev David McIlveen: "Deliberately offensive"

The Rev David McIlveen of the Free Presbyterian Church said the pair's use of nudity, language and certain materials was "sewerage for the presentation of art".

"I feel that this particular presentation of Gilbert and George brings in elements that are totally unacceptable to many people here in Northern Ireland.

"I would appeal to Gilbert & George to recognise the sensitivity of the people and to draw a line in the sand. There are things that are deliberately offensive."

But the artists believe they have never had a warmer welcome.

Appreciative crowds

"Many people are attending the show and loving it," Gilbert told BBC Radio 4's Today programme.

Gilbert: "Art is a much older tradition than Christianity"

"We had 300 people to tea on Saturday. Men, women and children - all very appreciative," he added.

"Art is a much older tradition than Christianity . Nudity has always been part of fine art," argued Gilbert.

"We use very very few words in our pictures which are not already in the Bible."

Angry members of the Free Presbyterian Church picketed the opening of the festival at Belfast's Ormeau Baths Gallery last week.

Gallery director Hugh Mulholland said they had expected some sort of "outrage".

But he said that Gilbert & George were "unquestionably among the most important and original artists of our time".