One of the UK’s most pervasive legal myths is that of ‘common law marriage’. Surveys repeatedly show that over half the population believe that a lengthy period of cohabitation and “living as husband and wife” brings them the same legal rights and entitlements as they would have had if they were formally married. This simply is not the case.

It is true that one acquires a small number of entitlements purely through an extended period of cohabitation (such as means-testing for welfare benefits, tax credits and access to non-molestation orders). Unmarried cohabitants may also be entitled to a share of their partner’s estate if they were financially dependent on them or, for the two years prior to their death, had been living in the same household “as the husband or wife of the deceased”. Their remedy, however, will be limited to that required for their maintenance, whereas spouses’ claims are not so limited.

Unmarried cohabitation gives no financial entitlements on separation and carries none of the tax benefits or automatic entitlements on death that married couples enjoy. Where there are minor children, it may be possible for a cohabitant to make a claim as the parent of the child, but this will be limited to maintenance unless the father is particularly wealthy. Otherwise, cohabitants are forced to fall back on trust and property laws written in times when ‘living in sin’ was socially unacceptable.

Unmarried cohabitation is increasingly common in the UK. In 1996 there were 1.5m cohabiting couples – by 2015 that figure was 3.2m. Meanwhile, over 30% of children born in the UK are to unmarried, cohabiting parents. In recognition of this, the Law Commission was invited nearly ten years ago to review the situation and make recommendations. Its report, in 2007, recommended introducing financial relief for qualifying cohabitants, but these plans were shelved by the coalition government in 2011 and seem unlikely to be resurrected. Certainly from a divorce standpoint, the best asset-protection advice for wealthy individuals remains to avoid marriage altogether.