A false bishop managed to hoodwink senior cardinals gathered at the Vatican to discuss arrangements for the election of the next Pope.
German-born Ralph Napierski was pictured with senior clerics as they arrived for the start of the College of Cardinals meeting - which Britain's most senior Roman Catholic Cardinal Cormac Murphy O'Connor was also attending.
Mr Napierski was seen shaking hands with unsuspecting Cardinal Sergio Sebiastiana outside the Vatican's Pope Paul VI hall, with several other priests in his entourage who were also thought to be bogus.
Alert Swiss Guards rumbled him because his vestments were wrong and because they noticed his purple sash was really a scarf and he was also wearing an odd-looking fedora hat. The other giveaways were the shortness of his black cassock and the crucifix around his neck on a short chain.
Before being spotted, Mr Napierski had told reporters his name was Basilius and that he was a member of the non-existent Italian Orthodox Church.
Initially there were reports in the Italian media that he was part of a stunt by Australian TV, but this proved false.
Mr Napierski also said the Catholic Church had made "serious mistakes" by allowing priests accused of sex crimes to move to different parishes elsewhere and cover up scandals instead of dealing with them.
The imposter has a website in which he claims to be a bishop with a Catholic organisation called Corpus Dei. It shows him dressed in robes and he describes himself as a "slave and apostle like St Paul", although it is littered with spelling mistakes.
On YouTube, Mr Napierski has also uploaded several videos in which he describes the benefits of the "ancient hidden spiritual practice of Jesus Yoga" and his website goes on to add that he is "fighting the heresy and false movements inside the Roman Catholic Church".
Vatican officials tried to play down the incident with spokesman Father Federico Lombardi saying: "I'm not aware of this at all - I was inside the hall and all those inside were real cardinals."