The Year That Never Was was a year which, due to the destruction of the paradox machine, never occurred for a majority of the population of Earth, but was remembered by a few people on the Valiant. During this time, beginning with Day Zero in approximately Spring 2008 and lasting exactly one year and one day up to Launch Day in 2009, the Master, with the assistance of the Toclafane, ruled over Earth. However, once the year was erased from history, everything was restored to how it was, the Master failing in his efforts.
The Master, then calling himself Harold Saxon, won the upcoming general election and became Prime Minister of Great Britain and self-proclaimed ruler of the Earth, following the downfall of Harriet Jones. He had, by this time, converted the Doctor's TARDIS into a paradox machine in order to alter history. (TV: The Sound of Drums)
After the Master ordered the Toclafane to remove one tenth of the Earth's population, (TV: The Sound of Drums) Martha Jones travelled around London and started to tell people of the Tenth Doctor as part of his master plan. She rescued a little girl known as Aleesha and then travelled to Europe and met a man known as Mathieu Vivier. (PROSE: The Story of Martha)
Martha also met a man in Turkey known as Brigadier Erik Calvin. Eventually she went to spread the message to Japan but the Toclafane attacked, killing everyone there. Only Martha escaped the country. (PROSE: The Story of Martha)
Occupation of Earth
From his mobile base, the Valiant, the Master launched the Toclafane invasion.
The Master had enslaved the human race with the intention of using them to build weapons in preparation for war against the rest of the universe. The Master wished to turn Earth into New Gallifrey and create a new empire stretching across the universe, lasting "one hundred trillion years". (TV: The Sound of Drums / Last of the Time Lords)
The Master imposed a dictatorial and despotic regime upon the Earth with himself at the head of it.
The people suffered severe over-crowding, often with many families crammed into a single house, and economic and technological regress occurred massively in the neglected urban centres. One citizen claimed that London was "full of wild dogs" by night. Countless billions of human lives were lost over the course of the year.
Television and any notable technology was shut down, and entirely replaced with the Archangel Network. It was implied by Professor Alison Docherty that at some point a military response to the invasion was attempted, but the Toclafane descended.
The Master also carved his face into Mount Rushmore, and ordered statues of himself to be built across the world to enforce his regime. The effects on Earth were so great that the planet was closed to the wider universe, and the planet was designated to be unsafe to approach.
During the Master's time he was known to have frozen the River Nile, poisoned the Caspian Sea, (PROSE: The Story of Martha) built fusion mills in China, created radiation pits in Europe, (TV: Last of the Time Lords) burned the islands of Japan to the ground in retaliation for the Drast meddling and ruined New York City. (PROSE: The Story of Martha)
The leader of the resistance was Martha Jones, who became renowned among the human race for travelling across the world and evading capture by the Master. One of her more notable escapes was her escape from Japan, being the only person ever to do so.
She had escaped the Valiant using a vortex manipulator given to her by Jack Harkness and witnessed the slaughter of one tenth of the population of Earth. Many legends developed around Martha Jones and the purpose for her travelling the world. The most common belief held by people was that she travelled across the world in search of a weapon. Another belief held by the people was that Martha Jones was the only one who could kill the Master.
Members of the resistance included Thomas Milligan and Professor Alison Docherty, the latter betraying Martha to the Master in return for information about her son. A small resistance also existed on the Master's headquarters, the Valiant, headed by the Doctor. Members of this resistance included Francine Jones, Clive Jones, Tish Jones and Jack Harkness. (TV: Last of the Time Lords)
Eve of war
The Eve of War was the day before the Master planned to go to war against the rest of the universe. He chose this day to transmit a warning to Martha. He used his laser screwdriver to age the Doctor's body to his actual age of 900 years. (TV: Last of the Time Lords)
A revolt on the Valiant and the destruction of the paradox machine by Jack Harkness reversed time to just before the Toclafane's arrival on Earth. Everyone on the Valiant retained their memory of the year while the rest of the human race had no memory of the events under the Master's reign. (TV: The Last of the Time Lords)