Established in England in 1842 to cater to the middle classes (one of the requirements for membership was a minimum weekly wage of 24 shillings). In 1879 it had about 90 000 members and around 1900 about half a million members. It absorbed a number of other benevolent societies and in 2007 was bought by Reliance and Mutual Insurance Society.
Its English records (1842 - 2000) are at the City of Westminster Archives Centre1.
There was a unit in Toronto in 1921.
References:
(1) http://apps.nationalarchives.gov.uk/a2a/records.aspx?cat=094-2322&cid=0#0