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)

Roz Forrester, Danny Pain, Hamlet Macbeth, the Silurian singers Jacquilian and Sanki, Sherlock Holmes and John Watson wore royal blue cravats to Bernice Summerfield and Jason Kane's wedding in Cheldon Bonniface on 24 April 2010. (PROSE: Happy Endings). (PROSE: Happy Endings)

The Editor of Satellite Five wore a royal blue cravat. (TV: The Long Game)