The unmistakable pine fragrance of an indoor Christmas tree is the ultimate physical manifestation of Christmas.

Above the advent calendar, door wreath, mince pies, Yule log, crackers and Die Hard box set, it is the arrival of the tree that proclaims the festive season to be fully underway.

But could your carefully decorated foliage become a fairy-lit inferno that will burn your house down?

America’s National Institute of Standards and Technology (NIST) has made an alarming film titled “why you should water your Christmas tree”.

The footage shows small fires being started in the branches of two Douglas fir trees. The film makers said one had been “lovingly hydrated since its purchase five weeks earlier”, while the other tree “didn’t get a drop”, during the same time.

Within seconds of ignition, the unwatered tree explodes into violent flames, setting furniture on fire and bringing an apocalyptic end to the festive scene.

Meanwhile, the small fire lit in the branches of the tree that has been watered struggles to get going.

After a minute and a half, the fire in the watered tree has all but puttered out. Meanwhile the dry tree has fuelled a colossal roaring fire that could have deadly consequences.

The NIST said the ignition of the trees was similar to that of an electric short from fairy lights, or a candle being placed too close to a tree.

London Fire Brigade has shared a similar video on its Twitter page warning of the hazards of Christmas lights on a dry unwatered tree.

In its video, the entire room has caught fire in less than 40 seconds.

London Fire Brigade’s group manager for community safety, Mark Hazelton said: “Check your Christmas tree lights are in good condition, turn them off before you go to bed and be safe at home over the festive season. Keeping your tree well watered can also prevent fire from taking hold.”

The organisation also urges people to make sure they have working smoke alarms.

In order to water your Christmas tree you will need a firm base for the tree with a water reservoir that ought to be topped up daily.

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Fake plastic Christmas trees do not require watering, but lights still ought to be switched off before bed.

London Fire Brigade also issued a warning about the risk of unattended candles over the Christmas period.

“At this time of year, many people will be lighting candles as part of their festive decorations but if you don’t use them safely it could spell disaster for you and your family.