31 December

31 December was the final day of December when many Earth-based cultures celebrated New Year's Eve.

It was not a well-known holiday in the Second Great and Bountiful Human Empire, as Sara Kingdom did not recognise it. (TV: The Daleks' Master Plan)

Amongst the notable things that occurred on this day were:
 * 1879 - Queen Victoria issued the Torchwood Charter and founded the Torchwood Institute. (TV: Children of Earth: Day One)
 * 1899 - The Torchwood One agent Gerald Kneale assisted Torchwood Three with the Centurian Incident and its clean-up in Cardiff. (COMIC: Rift War! Part Six: Circles)
 * 1926 - The Marylebone Cricket Club (MCC) played All India in the 2nd Unofficial Test match of the scene in Calcutta, British India. The MCC won the match by four wickets. The Fifth Doctor considered it to be one of the best cricket matches of all time. (AUDIO: The Emerald Tiger)
 * 1930 - The Eighth Doctor finally brought Charley Pollard to the Raffles Hotel in Singapore, but an old enemy of the Doctor soon forced them to leave for a whirlwind tour of history. (AUDIO: Seasons of Fear)
 * 1965 - Chasing the Daleks, the First Doctor briefly materialised his TARDIS in Trafalgar Square during the New Year's Eve celebrations. (TV: The Daleks' Master Plan)
 * 1986 - Ben and Polly reunited long after their travels with the Second Doctor had ended. They reflected on their time with him. (PROSE: Mondas Passing)
 * 1993 - Tko-Ma tried to escape his dimensional prison. He was stopped by the Sixth Doctor. (PROSE: Instruments of Darkness)
 * 1999 - Inside the Walker General Hospital morgue, after having his regenerative ability delayed by anaesthetic, the Seventh Doctor regenerated into his eighth incarnation, forced his way out, and discovered his memories were gone too. The Doctor tried to convince Grace he was the same man she attended the previous day, and recruited her to help him with his bout of amnesia, eventually regaining his memories. Meanwhile, Chang Lee, having pocketed the Doctor's TARDIS key, began raiding it. The Master found Chang Lee in the TARDIS and manipulated him to open the Eye of Harmony. Opening the Eye destabilised Earth's physics and the Master used it to begin stealing the Doctor's lives. The Doctor helped Grace put the TARDIS in a temporal orbit, draining the power from the Eye and thwarting the Master. After the Master killed Grace and Lee, the Master fought the Doctor and fell into the Eye. The TARDIS reversed Lee and Grace's deaths and closed the Eye. (TV: Doctor Who)
 * 1999 - The Sixth Doctor and Melanie Bush saved the Earth from being taken over by Saraquazel, a being from the after-universe, and his servant Ashley Chapel. (PROSE: Millennial Rites)
 * 1999 - A younger version of the Seventh Doctor and an older version of Mel gate crashed the New Year's Eve party being thrown by Alisha Hammerson, the Auton head of Hammerson Plastic PLC, in London. They foiled her plan to replace her guests with Auton replicas so the Earth could be dominated and absorbed by severing her link to the Nestene Consciousness. (COMIC: Plastic Millennium)
 * 1999 - The Fourth Doctor stopped the Y2K bug as the New Year arrived. (PROSE: Millennium Shock)
 * 1999 - While Jack Harkness fought a "Millennium Bug" of his own, Alex Hopkins killed the rest of his Torchwood Three team, then himself after Jack returned, just as the New Year arrived in Cardiff's time zone. He had been driven insane by a psychic locket that showed him dark things awaiting in the future. Hopkins tricked Jack to leave the Hub because he was immortal and would have prevented Hopkins' "mercy killings." Harkness subsequently took over Torchwood Three, given the leadership by Alex just before he claimed his own life. (TV: Fragments)
 * 1999 - Dave Young spent the entire evening trying to convince his girlfriend, Anji Kapoor, that the millennium wouldn't actually begin for another year. Kapoor, for her part, thought this extreme pedantry meant their relationship was in trouble. This incident led to her insisting on New Year's Eve 2000 that the two of them spend 2001 doing "Wild and Spontaneous Things' — the result of which was the couple spontaneously going to Belgium in February 2001. There, she met the Eighth Doctor and began travelling with him. (PROSE: Escape Velocity)
 * 1999 - The renegade Time Lady Iris Wildthyme and her companion Panda arrived in San Francisco in her TARDIS. Immediately after their arrival, Iris spilled gin into the bus' control and out into the Time Vortex, resulting in various different versions of Panda from alternative realities crossing over into the primary universe. With the assistance of Dr George Strangeways, Iris was able to close the rift, though not before the Panda from the primary universe had been dragged into it. (AUDIO: The Panda Invasion)
 * 1999 - "Dara Morgan" suddenly came to being, and registered MorganTech. He was broadcast live on a news channel that same day. (PROSE: Beautiful Chaos)
 * 1999 - In an alternative timeline, the Fifth Doctor, Peri Brown and Erimem visited Edinburgh. (PROSE: Graham Dilley Saves the World)
 * 2004: Rose Tyler missed a New Year's Eve party, thereby allowing her to unwittingly meet the regenerating Tenth Doctor, prior to her first encounter with the Ninth Doctor. (TV: The End of Time)
 * 2007 - The Eighth Doctor and Charley Pollard arrived at 8:00, and witnessed New Year's Eve. They had intended to go to 1931, Charley's time, as she wanted to leave. The TARDIS had brought them to the wrong time because of a time hump on 17 January 1942. (AUDIO: The Girl Who Never Was)
 * 2066 - Jack Harkness visited a bar on Zog. There, an individual of an unnamed species gave him instructions for the either earlier or later version of him. This version, upon opening a box on 7 August 1941, relived these experiences. (COMIC: Overture)
 * 2599 - A New Year's Eve party at the Braxiatel Collection was interrupted by murder. (PROSE: The Doomsday Manuscript)