Over the last few decades, there has been a considerable shift in the make-up of the British family.

The advent of civil partnerships and same-sex marriages has amounted to an enormous change. However, the preference of an increasing number of couples to live together without marrying has arguably had more impact.

In previous generations, such an arrangement would have been a source of social stigma, but no more. During the course of the last 20 years, the number of cohabiting couples in England and Wales has more than doubled.

Data published last November by the Office for National Statistics (ONS) on the matter revealed that there are now 3.2 million unmarried couples in the country.

Even though cohabitation is a more common and well-accepted domestic arrangement, there is still a lack of knowledge about its status in law.

More than half of the individuals who took part in the British Social Attitudes Survey in 2008 believed that living together for any length of time made partners ‘common law spouses’ with similar rights to their married counterparts, something which is not the case.

Various moves have been made to correct that disparity, albeit without substantive progress at the time of writing. Four years after the Government rejected the Law Commission’s demand to introduce cohabitation law in 2011, the Liberal Democrat peer Lord Marks’ Private Members’ Cohabitation Rights Bill had its first reading in the House of Lords.

There are, of course, cohabitation agreements in existence, which provide unmarried couples with the means to determine ownership of respective assets should their relationship not last the course.

To some, they seem unromantic and add an element of formality to an arrangement which is by its very nature more casual than marriage.

Nevertheless, they potentially forestall the kind of dispute which has featured at the Central London County Court in recent days.

Gareth Powell is suing his former girlfriend, Chloe Thomas, for the value of renovation work which he did on a flat which was owned by – and shared with – Miss Thomas.

Whereas Miss Thomas had the funds to buy the apartment, Mr Powell, a builder by trade, borrowed money from his parents to make what was described as an “uninhabitable” property into one which was rather more desirable.

He alleges it had been agreed that, in return for his efforts, he would be entitled to one-third of the profit of the flat's sale at a later date.

After being left without a penny for his labours when they broke up in 2014, he demanded payment of the £60,000 which he maintains he is owed.

Sadly, although not every similar case makes the newspapers, the row between this couple is all too familiar and yet so easily avoidable.

Rather like a prenup for husbands and wives, a cohabitation agreement can make the business of dividing assets on break-up more an administrative exercise and less an emotional rollercoaster.

It’s particularly true in situations where the property in which a couple live is registered in the name of one partner alone.

Without wishing to prejudge the outcome of Mr Powell’s case, (in May 2016 a court ordered Miss Thomas to pay her former boyfriend £50,000 in respect of the value of the property and to pay court costs – a total bill of around £200,000) claims of this kind are surprisingly common, not least because either of the cohabitees can relatively easily accrue what is known as a ‘beneficial interest’ in such a property. Making home improvements is one frequently cited way.

By not being level-headed and adopting a cohabitation agreement – a kind of relationship insurance policy – couples make parting not “sweet sorrow”, as Shakespeare put it, but a source of friction.

As both Mr Powell and Miss Thomas are now finding, the document would possibly have avoided the uncertainty and expense of court action and might have allowed them to remain on better terms, even after going their separate ways.