Real First Contact

Real First Contact was a term applied to the official first contact between humans and aliens. However, the usage of the term was disputed as historians were never able to reach a consensus over when the Real First Contact was made. Some chose to count the Arcturan Treaty of 2085, citing that as an official, peaceful contact; the first time that human and alien sat down and talked, rather than attempted to commit genocide. (PROSE: The Dying Days)

A day to come
Across thousands of years, mankind had been visited by aliens, leaving their trails across the archaeological strata and their subtle influence on human development. Through the centuries, visitors from other planets were worshipped as gods or hunted down as monsters. (PROSE: The Dying Days)

In the late 19th century, Jack Harkness told a Blowfish in Cardiff that the Earth was a century away from what he termed "official first contact", telling the Blowfish that he was "upsetting the schedule". (TV: Fragments)

In the late 20th century, as humanity began to venture out into space, they had reached a level of scientific understanding that allowed them to interpret the old legends and superstitions. They also now possessed a level of technology that allowed aircraft and radar to sweep the skies for unidentified flying objects. Alien spacecraft and other artefacts began to arrive on Earth with alarming regularity. (PROSE: The Dying Days)

The Doctor and the hoax
Even the Doctor appeared unsure as to when the Real First Contact occured. Witnessing the London UFO crash in March 2006, the Ninth Doctor saw it to be a genuine crash landing rather than an alien invasion. He went on to speculate to Rose Tyler that it may be the official first contact; with that in mind, he claimed that he would not interfere, choosing to leave the matter to humankind alone. "So maybe this is it. First contact. The day mankind officially comes into contact with an alien race. I'm not interfering because you've got to handle this on your own. That's when the human race finally grows up. Just this morning you were all tiny and small and made of clay. Now you can expand."

- The Ninth Doctor.

However, the Doctor soon found that the crash landing was infact staged by the Slitheen family of Raxacoricofallapatorius who, having infiltrated the British government, (TV: Aliens of London) attempted to start World War III by using the fabricated threat of an alien invasion to be granted access to nuclear weapons, intending to destroy the Earth for profit. This plot was ultimately thwarted by the Doctor. (TV: World War Three)

Later history
Following the Sycorax invasion of Earth on Christmas 2006, the Tenth Doctor claimed to Rose Tyler that it marked a "brand new planet Earth", that there was "no denying the existence of aliens now". (TV: The Christmas Invasion)