2000

The year 2000 was, as evidenced by statements by American news outlets and world-renowned chronologist Professor Wagg — the start of the third millennium. (TV: Doctor Who) This view was shared by at least one incarnation of the Doctor. (PROSE: The Novel of the Film) Despite the predilection of most humans to celebrate it as the beginning of the millennium, however, at least one other incarnation of the Doctor regarded it as the final year of the second millennium. (PROSE: Millennial Rites) This tug-of-war between the technical and common conceptions of the year was reflected in an argument between Anji Kapoor and her boyfriend Dave Young. He held fast to the view that 1 January 2001 was the beginning of the millennium, whereas she found this pedantry a reason to seriously consider leaving him. (PROSE: Escape Velocity)

2000 was also the year that Hourly Telepress published adventures of the Karkus. (TV: The Mind Robber, PROSE: The Wheel of Ice)

January
For the first ten minutes of 1 January, London was transformed into the Great Kingdom. Anne Travers sacrificed her life to return the universe to normal. (PROSE: Millennial Rites) The Sixth Doctor regenerated shortly after leaving Earth. (PROSE: Head Games)

Also in the morning of 1 January, the Eighth Doctor departed San Francisco after preventing from destroying the planet at the start of the year. Grace Holloway declined an invitation to travel with him and the Doctor did not agree to Grace's invitation for him to come with her. (TV: Doctor Who)

The Fourth Doctor and Romana II were also on Earth on the 1st; visiting Paris, much to Romana's chagrin as they had only just visited the city, albeit twenty-one years earlier. (COMIC: The Forgotten)

Some time after the departure of the Eighth Doctor, Grace Holloway discovered residue left over from her encounter with. Seeking to develop a human/Time Lord hybrid capable of regeneration, she began working for a genetics lab; which she later learned was actually a branch of MI6. (COMIC: The Glorious Dead)

February - December
On 10 February, Henry Louis Noone was born in St. Stephen's Hospital in London. (AUDIO: A Death in the Family)

Prior to Christmas 2000, the Eighth Doctor warned Chang Lee not to be in San Francisco on that date and for him to "take a vacation". (TV: Doctor Who)

Unknown dates
Chloe Webber was born to Trish Webber and Chloe's father. (TV: Fear Her)

Sally Morgan was born. (AUDIO: Project: Nirvana)

Parallel universes
In an alternate universe, the Eighth Doctor stayed in San Francisco after defeating and married Grace Holloway. He got a job as a professor at a university in San Francisco and happily lived a domestic life with Grace. (COMIC: The Glorious Dead)

Behind the scenes

 * References in the Doctor Who universe tend to indicate the year 2000 was the start of the millennium, rather than 2001, the technical start of that millennium.
 * Doctor Who and the Tenth Planet directly contradicts The Tenth Planet, the television story the novelisation is adapted from. The 1976 novelisation considers the First Doctor's regeneration having taken place in 2000, rather the 1986 placement the 1966 television story gave.