The Wire

The Wire was an energy being that, according to the Tenth Doctor, took the "essences" and "souls" of the television-watching population of Great Britain in 1953 for a few days before and during the coronation of Queen Elizabeth II. Because it's physical body was destroyed, the Wire's true form remained unknown.

Biography
After capture, the Wire was sentenced to death and executed by its people. It survived, though, and preserved itself as an energy being and escaped to Earth.

It concealed itself in television signals, transferring itself from set to set. It fed off the mental signals of human brains, paralysing them and sucking out their energy with electrical tendrils. This process left the victims mindless and faceless. The victim's consciousness remained intact, as seen when the Wire showed the Doctor a sampling of its victims on the televisions in Magpie's shop. The Wire used the image of a female to communicate with the outside world. It hoped to use this energy to manifest itself in corporeal form once more.

The Wire stole the face of Mr Magpie, who owned an electrical shop, but returned it to him and give him plans for then-future technologies (such as a portable television small enough to carry in one hand), promising him freedom after the completion of its simple two-phase plan: First, have Magpie sell cheap television sets all over North London so it could feed. Second, have Magpie connect the Wire (inside the portable television) to the television transmission tower at Alexandra Palace on Queen Elizabeth II's coronation day, June 2nd, 1953. Connected to the tower, the Wire would both transmit itself to the estimated three million viewers watching in the vicinity and transmit back energy it would use to reconstitute its corporeal body.

The Tenth Doctor trapped the Wire on a Betamax tape using a homemade video recorder. The Wire's victims were also restored to their normal selves. The Doctor seemed confident that the Wire would remain trapped, but said that he would tape over it, just to be safe. (TV: The Idiot's Lantern)

The Doctor accidentally released the Wire whilst looking for his copy of It's a Wonderful Life. He trapped it in a small suburban house, where Alice Wu helped him to recapture it. (PROSE: Loose Wire)

Personality
The Wire was cheerful by nature at first, hardly ever degrading from a genial smile and a bright attitude. Underneath its happy-go-lucky exterior, the Wire was a calculating and sadistic maniac with no scruples or moral compass and lack of any ethical capacities. It laughed maniacally whilst consuming the souls of others and taunted the Doctor on his apparent failure before its defeat. It remarks that its own people tried to execute it, suggesting that it was a dangerous criminal. The Wire was, though, not only murderous and sadistic but rather intelligent, shown by how elaborately it planned to absorb the minds of London. When it tried to feed off the Doctor, it remarked that he was particularly nutritious, due to the brainpower of a Time Lord, and even commented on his genius. However, it knew when to back down at times, retreating after he threatened it with his sonic screwdriver. The Wire complained of an intense hunger, which meant that it needed to feed off the souls of other life forms in order to survive, and it had to do so repeatedly quickly to do so.

Behind the scenes
The Wire was based on Annette Mills, a children's television host in the 1930s, known to start off her show For The Children, Watch With Mother with the phrase "Are you sitting comfortably? Then I'll begin."

According to the non-narrative sources Doctor Who: Creatures and Demons and Doctor Who: The Ultimate Monster Guide, the Wire escaped to Earth through the communications device of one of its executioners, who was illegally recording the execution. Also, Doctor Who: The Encyclopedia reveals its planet of origin to be Hermethica.