Through a complex series of calculations, Mr Camping has arrived at the date of May 21, 2011, as Judgment Day, when only true believers will be spared.

But if you're not quite ready for the Rapture, there's no need for total despair … yet. Saturday is just the beginning of the end. The final fiery ball of damnation won't visit us until October 21.

Mr Camping bases his calculations on a model in which the number 5 equals ''atonement'', the number 10 equals ''completeness'', and the number 17 equals ''heaven''.

Miraculously, the square of the multiple of those numbers produces the exact number of days from the birth of Christ to the day of judgment. (For a full analysis of his approach, see refutecamping.com.)

Bonkers though it may seem to the non-believers, enough people have been convinced by Mr Camping's reasoning that by 2007 his organisation had assets worth $US122 million ($115 million), according to ministrywatch.com, a website that assesses the suitability of various Christian groups as recipients of donations.