Blue Daleks were Daleks bred to be non-commissioned officers. Slightly smarter than the grey Warrior Daleks but without the higher-ranking Red Daleks, Black Daleks and Gold Daleks' levels of autonomy, they served as the equivalent of sergeants and corporals. The Eighth Doctor told Sam this when she asked about the differently coloured Daleks milling about their city, some of which were blue.

During a trial of Davros conducted to root out traitors who sided with him, Blue and Red Daleks filled the room back to the walls behind the higher ranking Daleks. In the ensuing war a Blue Dalek in Davros' resistance was in command of a detail that was setting up bombs in the lift shafts to destabilise the structure of the city's control centre building. Under fire from the Dalek Prime's forces he continued to work on priming the first bomb but as the Daleks beside him were killed he made the decision to abort the countdown and detonate the bombs. The structure was weakened but remained intact. (PROSE: War of the Daleks)

Some Humanised Daleks with blue casings were discovered on the planet Kyrol. (COMIC: Children of the Revolution)

Other Blue Daleks[]

The Dalek Time Controller had a blue casing. (AUDIO: To the Death, X and the Daleks)

During the Last Great Time War, the Dalek members of the Eternity Circle were mostly blue, with silver domes and globes. Other Daleks present at the Daleks' temporary base in the city of Andor on Moldox were silver with blue domes. (PROSE: Engines of War) During the war, the Daleks of the Dalek Scientific Division were denoted by blue domes and sense globes. (AUDIO: A Thing of Guile)

After the Time War, Strategist Daleks of the New Dalek Paradigm were identified by their blue casings. (TV: Victory of the Daleks) As a result of the many failures of the original Supreme, this design of Blue Dalek was eventually retired, save for the original Strategist. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)

The casing of a Dalek reconnaissance scout, though heavily rusted, bore faded light blue paint on its dome, grating section, weapons platform and sense globes. (TV: Resolution)

Behind the scenes[]

A Blue Dalek. (NOTVALID: Dalek Hack)