Hmmm, the Sensorite part 3 isn't the most Christmassy of episodes is it?
In the early days of Doctor Who the series generally ran during the winter. For the first three years the Doctor spent his Christmas with the Daleks, which probably says (in years 2 & 3 at least) that the BBC knew what their audience wanted! In the third year Christmas Day was, like this year, a Saturday. Doctor Who was on that day and in fact took time out from the massive 12 part Dalek Masterplan to enjoy a pantomime style episode with a Dixon of Dock Green substitute and a visit to the silent movie studios. It's true, as you'll see when we get to Episode 97: The Feast of Steven on 27th February next year. It's a barking episode that ends with Hartnell wishing everyone at home a very happy Christmas. Troughton decides to change things round a bit, so visits the Daleks in the run to Christmas, Power of the Daleks finishing on the 10th December 1966, and then emulates the Royal Family by taking a Scottish Holiday in The Highlanders which had episodes 2 & 3 on Christmas & New Year's Eves respectively. 1967 was spent fighting his double in The Enemy of the World so lots of pantomime antics there, while Christmas 1968 falls between the last episode of The Invasion and the first of The Krotons.
Jon Pertwee's first season started later in Jan 1970 so there's no Doctor Who on in Christmas 1969. This pattern was repeated for the next few years, but usually at some point over the Christmas Holiday there was a compilation repeat with the Daemons shown in 1971, The Sea Devils in 1972, The Green Death in 1973, Planet of the Spiders in 1974 and Genesis of the Daleks in 1975 (the first of MANY repeats for this story)
Tom Baker made his debut a couple of days after Christmas 1974 and then in subsequent years the show would take a small mid season break over Christmas until Power of Kroll in 1978 and Doctor Who's great Christmas Pantomime, Horns of the Nimon in 1979. 1980 saw another break mid season, and for the next four years the Season would start very early in January. However in late 1981 we were treated to Doctor Who's first official spin off, K-9 and company, including the traditional British Christmas fare of a black magic cult. For many years Broadcasters would go for odd ghost stories and the like over Christmas. Odd but.....
The 1986 season, The Trial of a Timelord, was delayed till the Autumn but thankfully over by Christmas a pattern that was planned to be repeated for each of Sylvester McCoy's three years. However Sylvester's second year starts late due to the Olympics making The Greatest Show In The Galaxy the last original Doctor Who story shown over the Christmas period.
Of course now we're used to the new Doctor Who being a Christmas Fixture, starting with David Tennant's debut, The Christmas Invasion, through the Runaway Bride, Voyage of the Dammed, The End of Time and this year's Christmas Carol with the Warbling Barbie. So settle yourselves down at 6pm with a glass of something nice and enjoy.
Happy Christmas! I'm off to church, got to project at our morning service., but have a good day whatever you're doing.