"A Happy Christmas to all of you at home!".
So said the First Doctor in 1965, at the conclusion of The Feast of Steven - Part Seven of The Daleks' Master Plan. This was the only episode of the Classic series to be broadcast on Christmas Day.
The episode is credited to Terry Nation, but was heavily reworked by Donald Tosh. It was long thought that this breaking of the fourth wall was an ad-lib on the part of William Hartnell, but this is not the case - it was scripted.
The episode was designed to be skipped over when the story was sold overseas - the ending to Part Six just about matching up with the opening of Part Eight (sort of).
When the series returned in 2005, the Christmas Special became a regular fixture.
The first was The Christmas Invasion that year. We had robot Santas, a lethal Christmas Tree, and the Doctor sitting down to a Christmas dinner. The snow turned out not to be real.
This story was followed by Attack of the Graske - an on-line game which also had a Christmas setting.
In 2006 we had The Runaway Bride. More robot Santas and lethal Christmas trees (explosive baubles). The snow turned out not to be real.
2007 delivered The Voyage of the Damned. Aliens celebrating Christmas above Earth in a replica of the Titanic - BBC and ITV having usually saved blockbusters like disaster movies for a Christmas premiere. The snow turned out not to be real.
In 2008 we had The Next Doctor. A Christmas setting, and Victorian London reminding us of Dickens. Again the Doctor has a Christmas dinner. Real snow this time.
David Tennant bowed out on New Years Day in 2010, but the first part of his final story was shown on 25th December 2009. This was The End of Time Part I. Just another Christmas setting. No snow at all.
Steven Moffat's first Christmas Special was 2010's A Christmas Carol - about a Scrooge-like figure who is changed over the course of a single night through visits from ghosts of the past, present and future. There are a whole load of Christmas Eve's on display. The real Santa (his name's Geoff) attends a party, though we don't actually see him. Real snow, though we are on an alien planet for a change.
The 2011 Special was The Doctor, The Widow and the Wardrobe. Another Christmas setting, and another alien planet which is snowy, and has trees which grow things which look like baubles. The Doctor visits Amy and Rory for another Christmas dinner at the end.
2012 saw another Victorian Christmas in The Snowmen. A Christmas setting, with killer snowmen (embodiments of the Great Intelligence).
Matt Smith stood down at Christmas 2013, just a month after the 50th Anniversary story. Peter Capaldi arrived at the conclusion of The Time of the Doctor. A town called Christmas, which is in permanent winter, so it's Christmas every day.
Capaldi's own first Christmas Special was 2014's Last Christmas. Another Christmas setting, and the presence of Kantrofari dream crabs led to appearances by Santa Claus and his elves, plus his reindeer, at the North Pole. Clara dreams a perfect Christmas morning, including the presence of her dead boyfriend. A stocking-filler satsuma is significant. Again, references to the sorts of movies we watch at Christmas. The story title comes from Wham!s Christmas hit.
2015's The Husbands of River Song, and 2016's The Return of Doctor Mysterio were consecutive stories, as there was no new series in 2016.
The former had River Song dressed in a red cape, with white fur trimmings, first appearing on a snowy world. The latter simply had a Christmas setting.
2017 gave us another regeneration, as Capaldi became Whittaker. But first he encountered his first incarnation, as played by David Bradley, in Twice Upon a Time. An ancestor of the Brigadier features - allowing us to witness the Christmas Truce of 1914.
Moffat had expected Chris Chibnall to have written the 2017 Christmas Special as the introduction to the 13th Doctor, but was surprised to find he wasn't ready. Rather than lose the prestigious slot, Moffat then came up with Twice Upon a Time - stretching out Capaldi's departure. As it was, Chibnall had no intention of keeping the Christmas slot anyway. He would produce New Year Specials instead.
Time will tell if Russell T Davies will want to retain New Year Specials - or to resurrect the Christmas ones...
Before I go - a special mention of Georgia Moffett - daughter of Peter Davison and wife of David Tennant, who played The Doctor's Daughter. It's her 37th birthday today.
Merry Christmas Everyone!!!