Tomorrow is Christmas Eve. Right? Well, sort of. For some, Christmas does not arrive for another fortnight. For them, there is a kind of double vision, as everything closes down for the Western Christmas, and then opens up again - while Christmas preparations are still under way.
At the Russian cathedral church in South Kensington, they have only just got past St Nicholas's Day - the original Santa Claus day, in early December.
The air has been filled with incense and medieval chanting, in recent days. The day after tomorrow, however the church will be as closed as your local superstore. Why have special services on the day that the congregation regards as Thursday12 December?
The Russians will celebrate New Year in tandem with everybody else - if rather more vigorously.
Vodka tends to flow generously. Christmas comes later, on 7 January. Kutya - a rich dessert made of wheat, honey and poppyseed - will be eaten. But, for the Russians at least, there is little of the traditional British feasting at Christmas.
For many of the Russian churchgoers, the obvious mass-marketing of the Western Christmas is baffling and disturbing.
"Our Christmas is more spiritual. This is more commercial," says one of the cathedral congregation.
Not that the Russian church is entirely oblivious to modern commercial life - a notice instructs you, as you enter: "Please switch off mobile phone before entering cathedral."
Serbs - brothers in the Orthodox faith - also see Western Christmas as a fortnight premature.
At the Serbian church in Ladbroke Grove, west London, icons cover the walls of a building that used to belong to the Church of England until the 1950s. In one corner, the priest is blessing special home-made loaves, the slavski kolac, which are specially made for St Nicholas's Day.
For some at the Serb service, there is a sense of double identity - they boast a native London accent, with Serb values attached. Most regard the delayed Christmas as a kind of bonus.
"On 25 December, I sit back and watch some good TV," says Milan Jankovic. "This way, I feel like I get two Christmases. I was made in England, you know."
His friend Novak agrees: "We reap the benefits of both."
When it comes to the Serbian Christmas meal, a mere turkey with trimmings seems modest by comparison.
Christmas Eve is reserved for fish and potato salad. But for Christmas Day, a pig or lamb is roasted on the spit.
Ukrainians, too, count the days differently. Of the Orthodox Christians, only the Greeks are already preparing for Christmas Eve tomorrow.
The disjointedness stems from the different calendars that are still in use in the Orthodox church. The West follows the Gregorian calendar, proclaimed by Pope Gregory XIII in 1582. Britain joined in a couple of centuries later.
Russia, meanwhile, stuck to the Julian calendar (named after Julius Caesar). Russia did not abolish the Julian calendar until after the 1917 revolution. Even then, the church re-mained firmly in the Julian camp; in effect, the new calendar was seen as a Bolshevik iniquity.
In some respects, the confusion is still there.
The anniversary of the October Revolution falls in November. Meanwhile, 7 January is - after years of being ignored - celebrated as a Russian national holiday.
Old and new are mixed and matched. And Russians and foreigners can wish happy Christmas twice.Reuse content