22/12/2016 09:03 GMT | Updated 23/12/2017 05:12 GMT

No Formula For Christmas Number 1

© John Robertson / Alamy

Just a few more days until December 25 and we are in the midst of another Christmas Number 1 race - a tradition as British and festive as turkey and all the trimmings.

Whoever wins this year will have big shoes to fill after 2015's nail-biter between Justin Bieber and the Lewisham & Greenwich NHS Choir, a race which went right down to the wire, one tweet by Bieber changing everything...

A year later and this year's victor (barring a massive shock) is likely to come from the ranks of either Clean Bandit's Rockabye, Human by newcomer Rag 'N' Bone Man, or maybe Touch by Little Mix. None of them are particularly Christmassy songs, of course, but not all Christmas Number 1s are.

Remember Pink Floyd's Another Brick In The Wall, Human League's Don't You Want Me, Girls Aloud's Sound Of The Underground, Whitney Houston's I Will Always Love You, Yazoo's Only You? Christmas Number 1s, the lot of them. You don't need sleigh bells and a snow-filled video to be a Christmas chart-topper. Sometimes, you just need to have a stone-cold, well-timed smash hit record. It's no more complicated than that.

It is a timely reminder that there is no cast iron formula for a festive chart-topper. For sure, there are trends and fashions, which evolve from era to era - but no definitive recipe.

The past 12 years have seen the race dominated on the whole by two different types of contender - the X Factor-winning star (see Shayne Ward, Leona Lewis, Alexandra Burke etc) and the emotionally charged campaign release (such as the Military Wives (2011), Justice Collective (2012) and the Lewisham & Greenwich NHS Choir (2015)), who have all been among the recent victors - as well as 2009's Rage Against The Machine protest.

But there is more to the history of the Christmas race than this. Although it is a long time since a genuine Christmas song topped the festive chart, historically, many Christmas No1s are among the most celebrated Christmas songs of all time - Band Aid's Do They Know It's Christmas, Slade's Merry Christmas Everybody, East 17's Stay Another Day, Cliff's multiple winners, and so on.

Plus, of course, the novelty hit has a treasured place in the annals too, thanks to the likes of Can You Fix It by Bob The Builder, Mr Blobby, the St Winifred's School Choir, Ernie (The Fastest Milkman In The West), Lily The Pink and Two Little Boys.

For all the changes through the years, the Christmas Number 1 remains a coveted honour to this day. The week of the festive race remains the biggest, most high profile chart week of the year, often with the biggest sales of the year too. Plus it is impossible to overlook the history and heritage - Christmas in Britain wouldn't be the same without the Christmas Number 1 race, a tradition which is unique to Britain, part of our cultural history.

Of course, the biggest change in recent years is the move to a race which is pretty much 100% digital. Until recently, the biggest, most mainstream Christmas hits came with a CD single release (as well as the download and stream), most notably the X Factor releases. And of course what used to buoy the Christmas Number 1 race was gifting - a seven inch or CD single of the Christmas Number 1, neatly wrapped under the tree, a perfect Christmas gift.

But barely any of this year's contenders (barring the London Hospice's Choir's The Living Years, which was available as a CD single) will be available to buy in any shop. In 2016, digital downloads and streams rule the roost.

As a result, today's Christmas Number 1 reflects its pure popularity - whichever track emerges victorious when the Christmas Number 1 is unveiled as the winner of this week's race (on BBC Radio 1 this Friday from 4pm to 5.45pm, the full Official Chart Top 100 will be published on at 5.45pm) will, plainly and simply, be the most popular track of the moment across both track stream and download sales.

It is a striking fact that this year's three leading contenders are also currently the three biggest selling singles of the week, as well as being hugely popular on streaming services.

Whether the shift away from X-Factor winners and campaign releases in 2016 is part of a long-term trend only time will tell. But as the music world has evolved over the past half century, the Christmas Number 1 race continues to do so.