A Serjeant-at-Arms or Sergeant-at-Arms is an officer appointed by a deliberative body, usually a legislature, to keep order during its meetings. The word sergeant is derived from the Latin serviens, which means "servant".
The term Sergeant can be given two main definitions; the first being a military role and the other a governmental role. Whereas technically the two roles were not mutually exclusive, they were very different in roles and duties. The soldier sergeant was a man of what would now be thought of as the 'middle class', fulfilling a slightly junior role to the knight in the medieval hierarchy. Sergeants could fight either as heavy to light cavalry, or as well-trained professional infantry, either spearmen or crossbowmen. Most notable medieval mercenaries fell into the 'sergeant' class, such as Flemish crossbowmen and spearmen, who were seen as reliable quality troops. The sergeant class were deemed to be 'worth half of a knight' in military value. The office originated in medieval England to serve the Sovereign in a police role, much like a bailiff in more recent times. Indeed, the Sergeants-at-Arms constitute the oldest royal bodyguard in England, dating from the time of King Richard I (around 1189) as a formed body.
The Sergeant-at-Arms was a personal attendant upon the King, especially charged with arresting those suspected of treason. Richard I had 24 with him on the Crusades. They were formed into a 20-strong Corps of Sergeants-at-Arms by King Edward I in 1278, as a mounted close escort. In 1399 King Richard II limited the corps to 30 Sergeants, and King Charles II had 16. The number was reduced to 8 in 1685 and since then it has gradually declined.
The original responsibilities of the Sergeant-at-Arms included "collecting loans and, impressing men and ships, serving on local administration and in all sorts of ways interfering with local administration and justice." Around 1415, the British House of Commons received its first Sergeant-at-Arms. From that time onwards the sergeant has been a royal appointment, the sergeant being one of the Sovereign's Sergeants-at-Arms. The House of Lords has a similar officer.
The formal role of a Sergeant-at-Arms in modern legislative bodies is to keep order during meetings, and, if necessary, forcibly remove any members who are overly rowdy or disruptive. A Sergeant-at-Arms may thus be a retired soldier, police officer, or other official with experience in security. In recent times, however, the positions have often become quite ceremonial in some countries, with actual ability to eject members not necessarily being a primary requirement. The Sergeant-at-Arms of the House of Commons has general charge of certain administrative and custodial functions, as well as security within the chamber of the House.
Specific countries 
The Australian House of Representatives operates under the Westminster parliamentary system. The Serjeant-at-Arms is a career officer of the Department of the House of Representatives. The ceremonial duties are as the custodian of the Mace, the symbol of the authority of the House and the Speaker, and as the messenger for formal messages from the House to the Senate. The Serjeant has the authority to remove disorderly people, by force if necessary, from the House or the public or press galleries on the instructions of the Speaker. The administrative duties of the Serjeant include allocation of office accommodation, furniture and fittings for Members' offices, coordination of car transport for Members, mail and courier services for the House, security for the House and arrangements for school visits. Once a meeting has started in a House the Serjeant will usually stand at the door to keep authority and make sure no one else comes in or out.
The Serjeant-at-Arms is the senior official of the National Parliament (Jatio Sangshad) who is responsible for maintaining order during sessions and to maintain security and protocol at Parliament under the guidance of Speaker. Presently, Captain M Ashraful Haque, a Navy officer, is Serjeant-at-Arms.
The Sergeant-at-Arms is the senior official of the Canadian House of Commons. In this role, the sergeant-at-arms is responsible for the building services and security of the House of Commons, and is appointed by the Governor General acting on the advice of the Federal cabinet. The sergeant-at-arms carries the mace, the symbol of the authority of the House, in the daily parade into the House of Commons chamber. The current Sergeant-at-Arms is Kevin M. Vickers. Provincial legislative assemblies, houses of assembly, national assemblies, and provincial parliaments (the nomenclature for legislatures varying between provinces) also employ sergeants-at-arms for similar purposes.
The Knesset of Israel has a sergeant-at-arms (officially known in Hebrew as "קצין הכנסת" ("k'tzin ha-Knesset"), (lit. "Officer of the Knesset", but as "sergeant at arms" in English). The sergeant-at-arms is the commander of the Knesset Guard.
New Zealand 
The New Zealand House of Representatives operates under the Westminster parliamentary system. The Serjeant-at-Arms is a permanent Officer of the House and controls the Chamber & Gallery Section comprising 20 officers, including a Deputy Serjeant-at-Arms and two Assistant Serjeants. An additional role of Parliamentary Support Service Manager is undertaken, which is in charge of the Reception and Telephone Services comprising 7 staff. Duties in addition to normal management, financial and people capability tasks are in relation to the House security and maintaining good order in conduct of visitors (strangers) visiting the Gallery areas, Officials attending the House for Ministers, access controls to the doors to the floor of the House, lobbies and the on the floor of the House as directed by the Speaker. There is a major ceremonial role with the Mace for the Speakers Procession and other events such as the Commission Opening, State Opening and the Commissioning of the Speaker. When working with the Deputy Speaker and two Assistant Speakers (Presiding Officers)in the chair the same rules from the Speaker apply for the Serjeant's duties in the House. The Serjeant is an employee of the New Zealand Parliamentary Service. When the House sits he is only answerable to the Speaker. For the Parliamentary Support Services Manager duties the position reports to the Group Manager Precinct Services. For the House business the Serjeant and his Chamber & Gallery staff work very closely with the Clerk of the House.
The current Serjeant-at-Arms is Brent V Smith
South Africa 
The Serjeant-at-Arms is a member of the parliamentary staff who acts as the official guardian of the mace, a decorated rod which is the symbol of the authority of the Parliament of South Africa. The mace must be in position in the National Assembly Chamber during a plenary sitting.
The Serjeant-at-Arms is also responsible for maintaining the attendance register of the Members in the House. S/he must also maintain order in the House and remove people from the House as ordered by the Speaker.
According to the National Assembly Rules, "the Serjeant-at-Arms shall remove, or cause to be removed, any stranger from any part of a Chamber which has been set apart for members only, and also any stranger who, having been admitted into any other part of the Chamber, misconducts himself or herself or does not withdraw when strangers are ordered to withdraw."
The current Serjeant-at-Arms is Godfrey Cleinwerck. He is attired in a black tailcoat, smart waistcoat, starched white shirt, bowtie and white gloves. The Usher of the Black Rod is Vincent Shabalala whose duty it is to escort the presiding officers of the National Council of Provinces into its Chamber.
Sri Lanka 
The Parliament of Sri Lanka was established in the form of the Westminster parliamentary system. The Sergeant-at-Arms second most important permanent officer in the Parliament, who heads his own department, the Department of the Sergeant-at-Arms. The Sergeant-at-Arms is appointed by the Secretary General of Parliament and is responsible for all ceremonial occasions as the master of ceremonies in Parliament, preservation of order, custody of the Mace, security, admission of visitors, allocation of accommodation within the House and supervision of galleries.
Responsible for security, by tradition he is the only officer authorized to carry a weapon inside the Parliament building and is assisted by the Parliament Police Division. Admission of visitors to the precincts of Parliament is controlled by the Sergeant-at-Arms.
The current Sergeant-at-Arms is Anil P. Samarasekara.
United Kingdom 
The Serjeant-at-Arms is responsible for security matters concerning the House of Commons; the equivalent officer for the House of Lords is Black Rod. The Serjeant, whilst in the Commons overseeing proceedings, can also escort MPs out of the chamber by order of the Speaker of the House. The post dates back to 1415, and was traditionally held by retired military or police figures.
The immediate past Serjeant-at-Arms was Ms. Jill Pay, who was appointed on 30 January 2008, having previously been Assistant Serjeant at Arms since September 2004. Her appointment was seen by some as controversial, as she was the first woman appointed to the role, and the first person recruited from the civil service rather than the police or military. The appointment also coincided with a downgrading of the security aspect with the appointment of a professional security coordinator for Parliament.
In November 2008, following the controversial arrest of Shadow Immigration Minister Damian Green, and subsequent search of his parliamentary office by the Metropolitan Police, who were given written consent to do so by the Serjeant-at-Arms without holding a search warrant, the Speaker of the House stated that the protocol would in future require a search warrant and his personal approval before such a search could happen.  The Speaker's assertion in this speech that the Police had failed in their obligation to inform the Serjeant-at-Arms of the fact that they required a warrant was denied by Assistant Commissioner Bob Quick.
Previous Serjeants were  were:
- Major General Anthony Peter Grant Peterkin, CB, OBE [served 2005-2008]
- Sir Michael Cummins, a retired Lt Colonel who served in Germany, Norway, Denmark, Aden and Kuwait and Northern Ireland, and joined the House of Commons staff in 1982 [served 2000-2005]
The current Serjeant-at-Arms is Lawrence Ward who was appointed on 1 May 2012 he was a previous Acting Deputy, and Assistant Serjeant-at-Arms.
United States 
The Virginia General Assembly, as well as the two houses of the United States Congress both maintain the position of Sergeant-at-Arms. For the houses of the United States Congress, the sergeants are charged with the maintenance of order on the floor of the chamber (in the House, he may "display" the mace in front of an unruly member as an admonition to behave); they serve with the Architect of the Capitol on the commission that oversees the United States Capitol Police and security for the Congress, and they serve a variety of other functional and ceremonial roles.
Other uses 
In imitation, a variety of other bodies—from state and local legislative houses (city councils, county legislatures and the like) to civic and social organizations have created posts of sergeants at arms, primarily to enforce order at the direction of the chair and to assist in practical details of organizing meetings.
- Parliament of Australia: House of Representatives
- Parliamentary Monitoring Group
- Parliament of the Republic of South Africa
- Jacobs, Luzuko; Momlezi Kula (June 2009). "Interview: Q&A". In Session (Cape Town: Parliamentary Communication Services) 9 (6): 26. Retrieved 9 November 2009.
- "The middle ranking civil servant who was snubbed by the Queen". Mail Online. 4 December 2008. Retrieved 5 December 2008. "Mrs Pay had already struggled to shake off questions about her suitability for a post which dates back to 1415...The job has traditionally gone to senior police or military figures but Mrs Pay's background is that of a middle-ranking civil servant. The role was also downgraded with the appointment of a professional security coordinator for Parliament...Contrary to normal protocol, the Queen declined to grant Mrs Pay - the first woman to hold the post - an audience when she was appointed amid claims there were concerns about her suitability."
- UK Parliament - Serjeant at Arms
- "Speaker's Statement". House of Commons Daily Debates. Hansard. 3 December 2008. Retrieved 5 December 2008. "I have reviewed the handling of this matter. From now on, a warrant will always be required when a search—[Hon. Members: “Oh!”] Order....A warrant will always be required when a search of a Member’s office, or access to a Member’s parliamentary papers, is sought. Every case must be referred for my personal decision, as it is my responsibility. All this will be made clear in a protocol issued under my name to all hon. Members."
- Winnett, Robert (5 December 2008). "Speaker's position untenable after police contradict Damian Green arrest details". London: Telegraph.co.uk. Retrieved 5 December 2008. "Mr Quick's letter, which was released to MPs yesterday, states: "The officers explained the nature of the investigation and the purpose of the search and were satisfied that the Serjeant at Arms understood that police had no power to search in the absence of a warrant and therefore could only do so with her written consent or that of the Speaker." The written consent was later provided."
- Hansard 9 Sept 2004
- Hansard 20 Dec 2004