For centuries the church was the major agency for recording births, deaths and marriages.
In July of 1837 British Parliament introduced civil registration of births, marriages and deaths. Registrations were made by local civil registrars who in turn forwarded information to the General Register Office (GRO) in London.
These reports where compiled every three months - which is the reason for indexes to British births deaths and marriages covering quarterly periods: January to March being reported as the March quarter, April to June as the June quarter etc.
In early years some births, deaths and marriages were not registered due to a resistance against civil registration. However by the mid 1850s most of the population had come to comply with the new laws.
The indexes are divided into volumes by year, then quarter, and then listed alphabetically. The State Library holds copies of these indexes for 1837 to 1980 on microfiche.
Alternatively you may register with the General Registry Office to search their indexes online. PDF copies of certificates may be ordered from the website for a fee. *Note: At present only births and deaths are searchable online.* (August 2018)
You may also search the indexes transcribed by volunteers at Free UK Genealogy on the Free BMD website.
(Note: Formerly birth, marriage and death records were located at Somerset House (until 1970) and then St Catherine's House (until 1997) in London.)
In the State Library you may access these databases for free:
Studio portrait of four unnamed children c. 1920