A locum is a person who temporarily fulfills the duties of another. For example, a locum physician is a physician who works in a place where the physician is absent or short-staffed. These professionals are still governed by their respective regulatory bodies, despite the transient or freelance nature of their positions.
The word locum is short for the Latin phrase locum tenens , which means “place holder”, akin to the French lieutenant . The abbreviated form “locum” is common in Australia, Canada, Ireland, Malaysia, Singapore, New Zealand, South Africa and the United Kingdom; Unlike in Latin its plural is locums . In the United States, the full length ” locum tenens ” (plural: locum tenentes ) is preferred, though for Some Particular roles, alternative expressions (eg, ” substitute teacher “) May be more Commonly used.
In the UK, the NHS moyenne HAS 3,500 locum doctors working in hospitals On Any given day,  with 17,000 Reviews another locum General Practitioners.  Many NHS holds with 51 private agencies. NHS figures show that approximately 80% of hospital locum positions are filled by agencies on this framework. The remaining 20% are filled by agencies working outside this agreement. Locum agencies are common reference points for doctors wishing to work in this market. According to a report published by the Royal College of Surgeons NHS spent approximately £ 467 million on locum doctors through agencies in the year 2009/2010.
On the other hand, GP locums (freelance General Practitioners) mostly work indépendamment (c. 75%) from locum agencies Either’re self-employed or freelance via GP chambers based on the NASGP’s Sessional GPSupport Team (SGPST) model. Some GPs in the UK have been used by the Primary Care Trusts (PCTs) to provide locum cover. However, PCTs were abolished in 2013 and replaced by the CCGs (Clinical Commissioning Groups).  CGCs are now starting to employ salaried GPs with locum roles. Locum GPs are expected to be flexible, adaptable, resourceful, professional, quick to establish relationships, familiar with different IT systems, and able to independently manage risks.
Advantages and disadvantages
Locums provide a ready means for organizations to fill positions that are either only temporarily empty or during which no long-term funding is available. Locumming also offers a wide range of work environments and specialization fields which a permanent employee may not encounter.  
(PET) to Foreign Medical Graduates before the start of their first professional experience in the UK Primary Care System. 
HOWEVER, the locum position aussi: has a number of Disadvantages – the transient nature of means clustering extra stress and work for the locums whenever will They Have to fit into a new position,  and for the hiring organization, this Generally means clustering que le required flexibility ( And often, the lack of a guaranteed income) has to be rewarded with high salaries.  These May in the long term create Higher costs for the hiring organization than Adding more full-time positions (especially in highly skilled, accredited professions, and Unlike the position in some where cheap professions temporary labor or significant use of interns Actually undercuts Wages and reduces total staff costs).
(4) locums may provide (1) a person who is a physician or a physician , or (2) a physician or a physician. Lesser-quality work (or be seen as posing such a risk, fairly or not).  Further, locums often experience resentment from permanent staff, for example because they are paid more, or because they are considered to be the responsibility. 
- Jump up^ “NHS locums need ‘checks and training ‘ ” . BBC News . 1999-04-21 . Retrieved 2010-01-20 .
- Jump up^ http://www.nasgp.org.uk/download/locumnumbers/nasgp_how_many_gp_locums_in_UK.pdf
- Jump up^ “Salaried GPs made redundant as PCTs ‘shut up shop'”. Pulse Today. 18 November 2011
- ^ Jump up to:a b c d e “Career Focus – Locum doctors” – Dr. Philip Morgan, BMJ 7074, vol. 314. 11 January 1997
- ^ Jump up to:a b Locum pharmacy – Pamela Mason, 2004, p. 11
- Jump up^ http://locumdoctor4u.com/PET.html]