"Common Law Marriage
It is a common misunderstanding that a couple will have established a "common law marriage" after living together for a period of time. This is not the case. Common law marriage does not exist in Scotland. Even if you have lived with your partner for many years, you do not have the same rights in law as a married person does. There was a type of irregular marriage called "marriage by cohabitation with habit and repute" which could apply to couples who had lived together and were thought to be married. This was rarely used in practice..."
http://www.scotland.gov.uk/Publications/2006/0 4/27135238/1
Prior to 2006 there were very few cases of MCHR in Scotland - perhaps on average of 2 a year - and for the most part they were related to claims on a deceased partner's estate or when marriages took place abroad and was not recognised here.
The law on MCHR was uncertain, difficult to apply and the chances of establishing a marriage was negligible therefore claims to financial provision unlikely. The main problems were;
The repute of marriage had to be "substantially unvarying and consistent". - Petrie v Petrie (1911) citing Cunningham v Cunningham (1814)
The intention to get married in the future was inconsistent with regarding oneself as married.
CHR was not available to couples who had lived together without ever pretending to be married or acquiring the reputation of being married.
Complications relating to previous and subsequent marriages.
Informal arrangements were considered too doubtful a basis on which to establish rights to welfare benefits.