The RSM of the Army School of Ceremonial (ASC) Anthony Carl Gibson, has passed on the definitive answer on saluting/paying respects on Remembrance Day ( and most other occasions I would suspect) . Can all veterans be briefed before any parades.

Remembrance; SALUTING or PAYING OF RESPECTS –
Saluting is Officers Only.
Other RANKS and Civilians come to attention for the Last Post.
Veterans – Your actions are as per enlisted RANK.
Civilians if wearing headdress please remove.

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