Until Friday 14 August, the Government is consulting on proposals that would give many cohabiting couples legal rights similar to those enjoyed by married couples or civil partners when relationships end or a partner dies. The intention is understandable. Many people mistakenly believe there is such a thing as a “common law marriage”, and some suffer genuine hardship when they discover that no such legal status exists.

But these proposals solve the wrong problem, and in doing so risk creating several new ones.

At the heart of the consultation is a simple question: should the law automatically impose rights and responsibilities on adults who have never chosen to acquire them?

At present, couples already have three straightforward ways of obtaining legal protection. They can marry. They can enter a civil partnership. Or they can sign a cohabitation agreement tailored to their own circumstances. Each of these routes shares one important feature: both parties actively choose to accept the legal rights and obligations involved.

The Government’s proposals would reverse that principle. Instead of legal rights arising through an explicit decision, they would arise automatically once a couple had lived together for long enough, or immediately if they had a child together. Couples who never intended to enter a formal legal relationship could find themselves subject to financial claims they never anticipated.

That is a significant shift in legal principle. In a liberal society, adults should normally be free to decide whether or not to enter legal relationships carrying long-term obligations. The role of the State should be to ensure that people understand the consequences of their choices, not to replace those choices with assumptions.

The proposals would also create considerable legal uncertainty. Marriage has a clear starting point. A wedding ceremony leaves no doubt about when legal rights begin. Cohabitation does not.

When exactly did a couple start living together? Were they genuinely living together “as a couple”? Did temporary separations interrupt the relationship? Was it sufficiently “enduring”? Research has long shown that couples themselves often disagree about when cohabitation really began. These proposals would invite courts to resolve exactly those disputes, increasing litigation and placing further pressure on already overstretched family courts.

Most importantly, however, the consultation pays remarkably little attention to behaviour.

Britain already faces record levels of family breakdown. Today, nearly half of all teenagers are not living with both of their natural parents. Contrary to popular perception, this is no longer driven primarily by divorce among married couples. It is increasingly the result of the breakdown of relationships between parents who never married in the first place.

That matters because marriage is not simply a legal contract. It is also a deliberate psychological commitment. Couples make an explicit decision about their future, publicly affirm that commitment and acquire a clearly defined legal status. Research on commitment has consistently found that these deliberate acts matter. My doctoral research found that marriage itself contributes to relationship stability independently of the characteristics that lead people to marry in the first place.

The Government’s consultation assumes that extending marriage-like rights to cohabitants can only improve matters. It never asks whether reducing the legal distinction between marriage and cohabitation might also reduce the incentive for couples to formalise their commitment. If marriage becomes progressively less distinctive in law, it is reasonable to ask whether fewer couples will choose it. Given the already high levels of family instability associated with unmarried parenthood, that possibility deserves careful consideration before any reforms proceed.

This matters not only for families but for the public finances. Family breakdown carries substantial costs for the welfare system and other public services. If Government is serious about reducing long-term welfare dependency, it should be cautious about reforms that may inadvertently weaken one of the strongest institutions associated with stable family life.

Supporters of reform often point to children. Of course children deserve protection. But they already have it. The law rightly requires parents to support their children regardless of whether they are married, cohabiting or separated. Children’s rights should never depend on their parents’ marital status.

That is a different question from whether adults should automatically acquire financial claims against one another. The consultation tends to blur those two issues, but they are not the same.

There is a better solution.

The real problem is not that cohabiting couples lack a legal route to protection. It is that too many people misunderstand the law. The Government should launch a sustained public information campaign explaining that there is no such thing as “common law marriage”, and making clear that couples who want legal rights and protections should marry, enter a civil partnership or sign a cohabitation agreement.

That approach would respect adult choice, preserve legal certainty and encourage couples to make informed decisions about the commitments they wish to undertake.

The Government has correctly identified a problem. It has simply chosen the wrong remedy.