The form of address used is based as much on custom, tradition and proper etiquette as it is on regulation. During my career (NCM and officer) I was instructed, taught, told, or simply absorbed that it is proper to call officer cadets “Sir” or affix “Mister” to their surname, as well as using their rank when addressing them. But the requirement was
situational and changed depending on a number of factors; the rank relationship to the cadet, the work or social milieu, the unit or corps, the stupidity level of the cadet. Of course, the use of ‘honorifics’ much more horrific is also common when dealing with the (ahem) young ladies and gentlemen, particularly those who don't get the point when justifiably hit with an idiot stick.
Yes, at that great congregation of officer cadets known as RMC, the common practice is to refer to cadets as “Mister ****” and the NCMs who interact with them on a day to day basis refrain from calling them “Sir”. That is the situation of a training establishment where the local custom (and perhaps local regulation) permits such. It will not always be so depending on the time and place. Ill-advised attempts by some junior (and occasionally senior) members to publicly treat subordinate officers as whale **** when inappropriate to do so has sometimes resulted in consequences for such members. However, let’s not forget more than one cadet has (justifiably?) incurred ridicule and wrath when succumbing to fantasies of self-importance. While a humbling experience, it can be a useful part of an officer’s education.
The use (military or civilian) of the title "Mister" was historically applied to "gentlemen". At one time the inmates at RMC (like their Sandhurst cousins) were referred to as "Gentlemen Cadets".
In
The Moon's a Balloon, David Niven related some of his experiences at Sandhurst.
"...We were called "Gentlemen Cadets". The officers and non-commissioned officer instructors were the pick of the whole British Army and the drill instructors were exclusively, the pick of the Brigade of Guards. Knowing that you were due to become an officer in eighteen months' time, the N.C.O.'s could call you anything they liked provided they prefaced it with a 'Mr. So-and-So, Sir.'
. . . we smiled nervously at each other as we awaited the ministrations of 'Robbo' [Company Sergeant Major Robinson, Grenadier Guards].
Rapidly and with the minimum of trimmings, Robbo explained that although it looked unlikely at the moment, we were supposed to be officer material and it had fallen to his unfortunate lot to try, within eighteen months, to transform this ' 'orrible shower' into being worthy of the King's commission.
"I shall address you as "Sir" because that's the orders but when you speak to me you'll stand to attention, look me right in the eye and call me Staff...got it?"
Scattered murmurs of ‘yes’, ‘right-ho’ and ‘jolly good’ were silenced by one of the mightiest roars in the British Army.
‘GOT IT!!!??? Now let me hear the answer, Gentlemen . . . ONE, TWO, THREE’ . . . ‘GOT IT STAFF,’ we roared back.
However the use of “Mister” is not reserved exclusively for Officer Cadets and Chief Warrant Officers. The title was applied in lieu of rank to subalterns in the Army (and similarly in the Navy) because these officers were gentlemen. In the case of RSMs (WO1/CWO) use of “Mister” probably evolved as a sign of respect for a ‘man’ who had reached such a high professional station that the ‘gentlemen’ (officers) of his regiment could speak to him on an almost equal footing.
And from a dusty old box of things I've retained over a career. When I attended BOTC at CFOCS Chilliwack the Warrant Officer and NCO instructors did not call the candidates “Sir”. Like most officer basic training establishments, they tended to segregate the OCdts (and 2Lts aka Thick Officer Cadets) from the serving soldiers. That is an appropriate way of doing things and perhaps one of the reasons why there is no readily available and singularly quotable reference on the subject of what to call cadets. There are no great herds of Gentlemen Cadets roaming at will in the CF, therefore there is little cause to think much of them.
CFOCS Officers' Handbook Edition 1 July 1985
Chapter 9 Forms of Address
1. On parade, an officer always addresses other officers senior to him, whether by rank or appointment as “Sir”. When a subaltern is addressed or referred to in an unofficial way, he is spoken to as "Mr. Smith" but in an official way he is referred to by his actual rank, i.e. "Lieutenant Smith”. Female officers should always be paid the same compliments as male officers of equivalent rank. The correct form of address for female officers is 'ma'am'.
2. When on parade a subaltern will address a captain as "Sir". At other times he may address him by his first name at the invitation of the captain being addressed . In some units the use of christian names and nicknames is customary but this should be very carefully indulged in by new officers. For equals in rank, be guided by the age of officers and length of acquaintance. Field officers should be addressed as "Sir" by captains and subalterns but it should not be laboured on or used so frequently as to make the conversation sound ridiculous.
3. Chief Warrant Officers, are addressed on parade by the title of their appointment, but off parade they are usually addressed as "Mr." and their surname. Squadron/Company Sergeant Major is a position, and only Master Warrant Officers holding such positions should be addressed as "Sergeant Major". They are also addressed as "Sir" by their juniors in rank.
4. In answering an Officer or Warrant officer, other ranks always say sir. Do not allow "Yes, Major", Yes, Lieutenant, or any other bizarre form to be used by your subordinates.
5. When entering the anteroom before dinner say “Good Evening Sir” to the senior officer present. Also if your Commanding Officer or any General or Field Officer enters after you, stand up and say “Good Evening Sir.” Do not click your heels at anytime nor stand to attention on entering the anteroom, or dining room.
6. Today there is a closer bond of comradeship between officers and men than ever before. A clearer understanding has grown up under modern democratic principles which in no way impairs discipline or the respect of the men for their officers. Danger will arise only if officers fail to learn to be friendly with their men without loss of dignity or respect, always realizing that "undue familiarity breeds contempt". Officers will not be on a first-name basis with any other rank.
"Speech is a mirror of the soul; as a man speaks, so is he."
And something that is (not surprisingly) similar.
"This is a re-print of the JUNIOR OFFICER’S GUIDE put out in 1959." . . .
http://army.ca/info/junior_officers_guide.php
Section IV
FORMS OF ADDRESS
(a) When entering the ante room before dinner say “Good Evening Sir” to the senior officer present. Also if your Commanding Officer or any General or Field Officer enters after you, stand up and say “Good Evening Sir.”
Do NOT click your heels at anytime nor stand to attention on entering the ante room or dinning room.
(b) On parade an officer should always address other officers senior to him, whether by rank or appointment as “Sir.”
(c) When a subaltern is addressed on parade or referred to in an unofficial way he is mentioned as “Mr. Smith,” but in an official way he is referred to by his actual rank, i.e. “Lieutenant Smith” or “2nd Lieutenant Smith.”
(d) Except on parade it is advisable to avoid addressing a Captain as “Captain Jones.” However if it is desirable for any reason to address an officer by his rank this form may be used. It is quite wrong to address a Captain as “Captain” without using his surname.
(e) Field Officers should be addressed as “Sir” by Captains and subalterns, but it should not be laboured, or used so frequently as to make the conversation sound ridiculous. It is not incorrect to address a Colonel or Major by his rank alone, but the possibility of appearing unduly familiar makes it advisable for junior officers to adopt this habit only after considerable length of service, and more than an ordinary acquaintance with the Senior. Obviously a subaltern is rarely in a position to do so.
(f) It is customary when meeting any officer of the Armed Forces in the street to bid him “Good Morning” whether you know him or not. It is for the junior to speak first. If he is of field rank he should also be saluted.
(g) Warrant Officers Class I are addressed on parade by the title of their appointment e.g. “Sergeant-Major Brown” but off parade they are usually addressed as “Mr.”
(h) Other Warrant Officers and Non-Commissioned Officers are always addressed by their rank.
(j) Private soldiers are always addressed by their surname only.
(k) Other Ranks address Officers by their rank and name except subalterns whom they address by using “Mr.” and their name. In answering an Officer or Warrant Officer, Other Ranks always say “Sir.” Do not allow “Yes, Major,” “Yes Lieutenant,” or any other bizarre form to be used by your subordinates.
But there are still corps differences.
http://regimentalrogue.com/srsub/army_customs_1956_sect5.htm
1. The R.S.M.
In some regiments, corps or units it is customary to address the R.S.M. as " Mr. ----," while in others he is addressed as "Sergeant-Major." An officer on joining his regiment or new unit should find out which custom is in use by asking the Adjutant or some other officer of the unit.
. . .
4. Address-by rank
When addressing a warrant officer, an officer should do so by using his military rank or appointment. That is to say a Company Sergeant-Major should be addressed as "Company Sergeant-Major." For procedure when addressing a Regimental Sergeant-Major see sub-para. 1
When addressing a non-commissioned officer, an officer should do so by using the N.C.O's rank and name. For example, a Corporal should be addressed as "Corporal Snooks."
CUSTOMS AND TRADITIONS OF THE CME A-JS-007-003/JD-001
http://www.admie.forces.gc.ca/dgcps/CME_customs_Split_internet/English/Chapter_5_Customs_Service.pdf
FORMS OF ADDRESS
8. In all military organizations, there is a strict code on how members should address both superiors and subordinates. This formal code has been developed over many centuries and was once commonly utilized but, since society has become much more relaxed, it is rarely used today to the full extent once practised. The military has found that, especially in combat situations where people are living closely together and orders must be followed without hesitation, it is imperative that the hierarchical culture be maintained. For this reason, the CME and all military branches continue to use this form of courtesy that stems from an awareness of people and a respect for others rights and feelings. It is not one-sided and should be observed by all, and extended to all. The guidelines for addressing both superiors and subordinates are explained in the following paragraphs.
9. All ranks shall address a more superior officer as “Sir” or “Ma’am” or by the appropriate rank; however, “Sir” and “Ma’am” should not be used so frequently as to make conversation awkward. Even during sporting events or relaxed social functions, proper forms of address are used unless permission is granted to use a superior’s first name. It should be remembered that these privileges are usually only granted for the duration of the event and that once a normal work routine is resumed the proper forms of address will again be used. Superior officers normally address junior officers by their first names.
10. Officers address all NCMs by their rank or, in the case of a Chief Warrant Officer, “Mister” as a preface to the surname. NCMs address other NCMs by rank, with the exception of Chief Warrant Officers. Chief Warrant Officers are not called “Chief” or “Warrant” but “Sir” by all subordinate NCMs. Only Chief Petty Officers may be addressed as “Chief,” with or without using the surname. Sergeant Major is an appointment and Master Warrant Officers and Chief Warrant Officers should be addressed as “Sergeant Major” only if they hold that appointment.
11. Following retirement, particularly in social and sporting events within the CME associations, CME Family members are encouraged to address one another on a first name or more relaxed basis. The use of former ranks is reserved for formal occasions such as parades in direct association with serving members, where retired members continue to respect the protocols of serving members, for obvious reasons.
12. Civilian spouses do not hold the rank of their military spouse. It is, however, polite to address the spouse of a superior as “Sir” or “Ma’am” until permission is granted to use given names.