A Military Writer's Handbook
Primer - The Parts of Speech

Voice

Verbs can be in the active or passive voice, depending on whether the subject of a sentence is doing something (active) or having something done to him/her/them/it (passive).

Active and Passive Voice
(Active) Lt Harvey forgot her briefing notes for the press conference.
(Passive) The briefing notes for the press conference were forgotten by Lt Harvey.

Because the subject of the sentence has done somethingforgotten her briefing notesthe first sentence, in the active voice, is preferred.

(Passive) The Royal Marine Special Boat Service and the Special Air Service were deployed as an advance party to secure the position.
(Active) The UN Security Council deployed the Royal Marine Special Boat Service and the Special Air Service as an advance party to secure the position.

The joint Special Service units and their task are the focus of interest here and not so much who deployed them. So, the first sentence, in the passive voice, is the best choice.