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)
Rogue, a bounty hunter, wore a single-breasted waistcoat of royal blue brocade on 1813. (TV: Rogue)
The Editor of Satellite Five wore a royal blue cravat. (TV: The Long Game)
