LIKE a jealous ex-husband with a masochistic streak, the UK Government is at it again, embarking on a fresh hunt for the “undeclared partners” of benefit claimants. This time, instead of rifling through the mail for love letters from RS McColl and Joseph Rowntree, perhaps they’ll be checking under the bed, or in the wardrobe. Failing that, they could examine the bathroom for extra toothbrushes, or sniff the pillows for traces of sexy aftershave.

MP Mhairi Black is trying to put a fly in the ointment by calling for a new law banning private companies from stopping benefit or tax credit payments – as Concentrix did on the basis of its laughable attempts at sleuthing – but it seems likely the government will still find a way to metaphorically spraypaint “SLAG” across the front doors of anyone suspected of harbouring a secret cohabitee.

If you want to get a sense of just how complicated the benefits system really is, get your hands on a copy of the Child Poverty Action Group’s Welfare Benefits and Tax Credits Handbook. You’ll need both hands, because the latest edition is 1740 pages long. It’s regarded as the benefits bible and it feels like one too, with its wafer-thin pages and dozens and dozens of chapters. But that’s where the similarities end – instead of “what would Jesus do?”, the questions tend to be along the lines of “what was reasonable in the circumstances?” and “could the claimant have been expected to know the rules?”

The section on couples is a minefield for the “it’s complicated” generation, whose domestic arrangements increasingly fall outwith the neat little boxes of single/married/divorced. CPAG advises that “if you do not have a committed emotional loving relationship that is publicly acknowledged, you can argue that you are not living together as a married couple”. Which sounds straightforward enough, until you consider what all those adjectives might mean to different people. Commitment? She won’t even update her Facebook relationship status. Public acknowledgement? You’ll be asking them to hold hands next. What is this, a romantic comedy?

Among the factors taken into account when deciding whether two people are cohabiting, rather than simply living together, are “Do you have a sexual relationship?” and “Is the relationship stable?” Many a relationship has crumbled under less scrutiny than this, without the obligation for anyone to answer such make-or-break questions in front of strangers at a first-tier tribunal appeal. Bizarrely, if two individuals can convince the powers-that-be they are living together for “care, companionship and mutual convenience”, they can argue they are not, in fact, living as husband and wife. Call me unromantic, but that combination sounds like the mundane reality for many a married couple, and perhaps even an aspiration for some. I wonder what would tip the scales back towards a ruling of cohabitation. Foot massages? Breakfast in bed? Signing off texts with a wink-and-a-kiss emoticon?

At the end of the day, surely what matters here is whether someone is misrepresenting their financial circumstances, as opposed to their feelings. Two people might be living together, might even be sleeping together, but that doesn’t automatically mean they’ll be sharing their resources, and that the lower-income partner is being “kept”. Do a tiny minority of people deliberately make false declarations and receive more benefit money than they should? Yes. But a 2013 survey found that British people believed nearly a quarter of benefit payments were fraudulently claimed, whereas the DWP’s own estimate was 0.7 per cent for fraud and an additional 0.9 per cent for “claimant error”. Given these tiny figures, it surely does not follow that everyone receiving benefits should be expected to provide, on demand, formal proof they don’t fancy their flatmate. It simply cannot be cost-effective to treat all claimants as guilty until proven innocent – which is why any large-scale “crackdown” by the Tories and their private-sector partners feels less like a prudent claw-back of cash and more like an attempt to degrade and humiliate anyone and everyone who relies on state support.

There are other more efficient ways to address the twin problems of benefit fraud and claimant error, and the Department for Work and Pensions cannot claim to be ignorant of them since it has funded trials of them through its Fraud and Error Reduction Incentive Scheme. It knows, for example, that in one recent experiment spanning five English local authorities and involving 2,655 residents, the use of various “nudge” techniques led to a significant increase in reports of changes in circumstances. The most effective approach was simply sending letters reminding claimants to report any changes: as a result of this some 15 per cent of recipients did so, compared to seven per cent of those in a control group. Overall, housing benefit overpayments totalling £52,000 were identified.

On the face of it, this sounds like the kind of humane, effective and theory-informed approach that should be rolled out nationwide. There’s just one snag for a government that has the dual aims of cutting the benefits bill and giving a swift kick to those who have the nerve to claim at all: during the same study period, £11,000 of underpayments were identified too. So will this kind of evidence nudge the government in the right direction, or will ideology lead them back down a punitive path that further erodes trust between the individual and the state?

Only time will tell.