Better cancel those holidays. We now have a date for Armageddon, and it's a week on Tuesday - August 22.

This information comes from no lesser source than the Wall Street Journal, where Bernard Lewis, President Bush's favourite historian, provides the details.

"In Islam, as in Judaism and Christianity," the professor writes, "there are certain beliefs concerning the cosmic struggle at the end of time - Gog and Magog, anti-Christ, Armageddon, and for Shiite Muslims, the long-awaited return of the Hidden Imam, ending in the final victory of the forces of good over evil, however these may be defined.

"Mr Ahmadinejad [the Iranian president] and his followers clearly believe that this time is now, and that the terminal struggle has already begun and is indeed well advanced. It may even have a date, indicated by several references by the Iranian president to giving his final answer to the US about nuclear development by August 22. This was at first reported as 'by the end of August', but Mr Ahmadinejad's statement was more precise."

Lewis continues: "What is the significance of August 22? This year, August 22 corresponds, in the Islamic calendar, to the 27th day of the month of Rajab of the year 1427. This, by tradition, is the night when many Muslims commemorate the night flight of the prophet Muhammad on the winged horse Buraq, first to 'the farthest mosque', usually identified with Jerusalem, and then to heaven and back (cf, Koran XVII.1). This might well be deemed an appropriate date for the apocalyptic ending of Israel and, if necessary, of the world."

This sort of quasi-religious scaremongering always finds a receptive audience in the United States, especially among Christians of the jihadist persuasion. At 90 years old, Professor Lewis may have completely lost his marbles, but he is still feted by the White House (vice-president Dick Cheney was guest of honour at his birthday party in April), and the Wall Street Journal describes him as "a sage". He is credited with coining the phrase "clash of civilisations" back in 1990 and now seems intent on making it a reality.

Nevertheless, Prof Lewis does manage to spot a few drawbacks in his alleged Iranian attempt to obliterate Israel. "An attack that wipes out Israel would almost certainly wipe out the Palestinians too," he writes. This "might well be of concern to the Palestinians", he says, "but not apparently to their fanatical champions in the Iranian government." (He seems to be assuming here that Iran already has a fully primed nuclear arsenal, which is plainly not the case, despite what many Americans imagine.)

He then suddenly demolishes his own argument with this caveat: "It is far from certain that Mr Ahmadinejad plans any such cataclysmic events precisely for August 22."

So why, exactly, did the Iranians choose August 22 as the date for giving their answer to the US about nuclear development? Probably for bureaucratic convenience. When they promised a reply "by the end of August", they didn't actually use the word "August", but the Iranian equivalent. If you look up the Persian calendar, you'll see that August 22 just happens to be the end of the month known as Mordad.

I don't suppose this will discourage the neocons from continuing to write such loopy, prophetic nonsense. Here's another of them, Michael Ledeen, formerly a key figure in the Iran-Contra scandal, and the Iraq-Niger yellowcake affair, predicting an Iranian nuclear test by November 5:

"The Iranians believe they now have all the necessary components for a nuclear bomb. The only question is how long it will take them to assemble and test it. Khamenei had hoped to be able to test an atomic bomb by the third week in October, but his scientific advisers recently told him they could not make that deadline. They are now aiming for November 4 or 5, the anniversary of the seizure of the American embassy in Tehran during the revolution.

"There is another November date our leaders should take seriously: the 25th, the anniversary of the disappearance of the twelfth imam, and thus the most significant date in the Shiite calendar. Reports from Tehran suggest that the mullahs would like to celebrate that anniversary with a big-time terrorist attack against America."

Utter tosh. Don't believe a word of it. Ledeen was not talking about this coming November, but November 2003. His original article is here.