Turn back time tonight ...

It won't come around for 111 years, and after that it will never happen again. At 8.02pm, the world will witness a time that is truly, triply palindromic. It will be 20:02/20.02/2002.

Read the time, the day, the month and the year forwards or backwards, in numeric form, and the result is the same, discarding punctuation. Moreover, every individual component - time, date and year - is identical, and every one is itself a palindrome.

That has happened only three times before - at 10.01 on 10 January 1001, at 11.11 on 11 November 1111, and at 12.21 on 12 December 1221. "And when they happened, nobody had digital watches to notice it," says Professor Peter Cameron, professor of mathematics at Queen Mary College of the University of London.

It can only ever happen once more, says Professor Cameron - at 21.12 on 21 December 2112. "It is impossible after that because there are only 12 months in the year." It's a game - just something interesting," he adds.

"It's like the fact the next date that looks the same held upside down is 6009. For mathematicians, it is the significance of the numbers that matter, not the form."

For once, there is no associated pronouncement of Nostradamus, and even the internet, home to a million woolly-minded ravings, is silent, according to one of the British Museum's experts on calendars, Silke Ackermann. "A couple of people have commented on it, and then there has been a deadly silence," she says. It is, though, a pleasing numerical symmetry-that seems likely to cause a bulge in the marriage statistics.

A straw poll of London's registry offices reports extremely brisk business for a weekday in February, with a number fully booked by couples, presumably of a mathematical bent.

The experience mirrors that of Germany a couple of weeks ago when registry offices had to open specially, even though it was a Saturday, when they are usually shut, as hundreds of couples decided 2 February 2002 (02/02/02) was an auspicious date for tying the knot.

They can all raise a glass to Sotades the Obscene, who invented the palindrome as a literary form in 300BC, and was subsequently thrown into the sea wrapped in lead by King Ptolemy II, for writing rude verse about him.

As for scientists of other persuasions, the second minute of the twentieth hour of the twentieth day of the second month of the second year of the third millennium is, to quote John Betts, horologist at the Greenwich Royal Observatory and Maritime Museum - self-styled Home of Time - "really a bit of a non-event."

"For horologists like me, I'm afraid mere coincidences of numbers are really not terribly interesting," he says.

Those of a more wishful frame of mind could take comfort from Uri Geller who is "sending out a psychic message" at the appointed hour that he says will "make your dreams come true".