Royal blue
From Tardis Wiki, the free Doctor Who reference
Royal blue was a deep, vivid shade of blue.
The Tenth Doctor wore a double-breasted overcoat of cinnamon brown Alcantara with peaked lapels and a royal blue lining. (TV: The Christmas Invasion-The End of Time)
Romana II wore a royal blue cravat when she met Zodaal in London during 1930. (PROSE: The English Way of Death)
The Sixth Doctor wore a waistcoat with royal blue stripes when he and Peri Brown met Toby the Sapient Pig in 1913. (AUDIO: Year of the Pig)
Rogue, a bounty hunter, wore a single-breasted waistcoat of royal blue brocade in 1813. (TV: Rogue)
The Editor of Satellite Five wore a royal blue cravat. (TV: The Long Game)
