2164

2164 was the date on a calendar found by Ian Chesterton upon arriving in London in the 22nd century, just before the defeat of the occupying Dalek Earthforce. He went on to suggest it looked like it hadn't been changed for some time and so it was unlikely to be the actual date. (TV: The Dalek Invasion of Earth)

According to some accounts, 2164 was the year in which the 22nd century Dalek invasion was launched. By one account, it was in 2164 that the Daleks subjected Earth to meteorite bombardments before seizing the planet which they occupied for a number of years before being defeated. (PROSE: The History of the Daleks)

By another account, Susan Foreman related to a researcher that the Daleks, having been defeated in the "far distant future" on Skaro by the Thals led by Ian Chesterton, the Daleks used their own TARDIS to travel into the past with the intent to wreak revenge on Ian's people or, better still, prevent Ian himself from being born. However, they were unable to go any further back than 2164 due to a leak in their fluid link. It was still 2164 when the Daleks were defeated and Susan was left on Earth by the First Doctor, after which she made contact with Terry, who sent her back to July 1964. (AUDIO: Whatever Happened to Susan Foreman?)

Behind the scenes

 * The Discontinuity Guide also claimed that "mankind's first major encounter with the Daleks", following the earlier Vulcan Incident, took place in 2164. It is further noted that, because this source claims the Fourth Doctor changed Dalek history so that Davros survived, this event would have occurred vastly differently if it happened at all in the new timeline.