The Law Commission has concluded that cohabiting couples with children, or those who have lived together for a minimum period, should have more protection if the relationship ends. The report says the financial value of each partner’s contribution during a relationship should be taken into account, but stopped short of awarding couples who live together the same rights as married couples.

Unlike in cases of divorce, cohabiting couples would not be expected to provide ongoing maintenance payments and there would be no principle that assets should be split equally.

The commission said: “Merely moving in with someone would not give rise to any entitlement to a remedy.

“There should also be an opt-out scheme for couples, giving them the freedom to make their own arrangements for what would happen to their assets should the relationship end.”

Stuart Bridge, the law commissioner responsible for the reforms, said: “More and more families involve couples who are living together but who have not married.

“The law that currently applies to resolve property disputes between such couples on separation is unclear and complicated, and it can produce unfair outcomes. This causes serious hardship not only to cohabitants themselves, but also to their children.

“The scheme we are recommending, in the light of consultation, is distinct from that which applies between spouses on divorce. It would not apply to all cohabitants and where it did apply would only give remedies relating to contributions made to the relationship.”

The plans leave it to ministers to fix the minimum period a couple should live together before they are eligible, but it suggests a minimum period of between two and five years.

The commission, which advises the government on legal reform, says the current law is “uncertain and expensive to apply and, because it was not designed for cohabitants, often gives rise to results that are unjust”.

The report says the majority of couples who live together wrongly believe they are protected by “common law marriage” and would be entitled to a share of the assets when a relationship breaks down.