The Doctor's scarf

The Doctor's scarf was a long, multicoloured piece of knitwear that was an important part of the Doctor's outfit during his fourth incarnation. When the Doctor, shortly after his third regeneration, had to accompany the Brigadier on a journey, he tried on several inappropriate costumes before settling on a vaguely bohemian outfit, which included a wide brimmed hat and a long scarf. (DW: Robot) The scarf had originally been made for the Doctor by Madame Nostradamus. (DW: The Ark in Space)

The Doctor once mentioned that, had he not produced a ball of string for Theseus and Ariadne, they would have unravelled his scarf to escape the labyrinth. (DW: The Creature from the Pit)

After his fourth regeneration, the Doctor unravelled his scarf in the TARDIS corridors, allowing his companions to follow him. (DW: Castrovalva)

Uses
The scarf proved to be useful, on many occasions, as something other than a piece of attire.


 * On the Nerva station, the Doctor unsuccessfully used it to try to deactivate the Auto guard. (DW: The Ark in Space)
 * It came in useful for measuring a puzzle. (DW: Pyramids of Mars)
 * Escaping from Count Federico's executioner (DW: The Masque of Mandragora)
 * Tripping Eldrad down a chasm. (DW: The Hand of Fear)
 * In the Matrix on Gallifrey to prevent the Doctor from falling down a cliff face. (DW: The Deadly Assassin)
 * As a lead to drag K9 about when his power had run down. (DW: The Invisible Enemy)
 * Climbing a mine shaft using the scarf as a rope (DW: The Creature from the Pit)

Behind the scenes

 * When asked to knit a scarf for the new Doctor, Begonia Pope was unsure of how long a scarf was required. She consequently used all of the wool she had been given, culminating in a ridiculously long scarf. The producers loved the scarf and, after it had been shortened slightly, used it for the Fourth Doctor's first story.
 * There were many scarves used during the Tom Baker era, including a much shorter "stunt scarf" for action sequences. The pattern and coloration varied from season to season, as did the overall length of the scarf.
 * When June Hudson was asked to design a new outfit for the Doctor at the start of Season 18, she was given the option to omit the scarf by John Nathan Turner. In the end, she decided the scarf had become too much a part of the Doctor's image to omit, and designed a new scarf to go along with the new Burgundy color scheme of the Doctor's outfit.
 * In VG: TARDIS, the Fourth Doctor's scarf can be seen in the drawing room.