Six months ago the release of I, Daniel Blake divided not just commentators but politicians too. The film showed a benefits system that sets up too many to fail, unfairly treated by labyrinthine and heavy-handed rules. A blunt portrayal, perhaps, it nevertheless resonated widely – particularly the experience of the character Katie Morgan, a single parent trapped between wanting to study and provide for her family, and draconian benefit rules.

In response to the outcry, though, the government stuck resolutely to its guns. The Department for Work and Pensions secretary, Damian Green, describes sanctions as a necessary “backstop for the tiny minority” that break the rules. Conservative backbenchers clamouring to defend the policy repeat the department’s mantra that over 90% of jobseeker’s allowance claimants aren’t sanctioned. What clearer indication is there that the public furore is mere sound and fury, righteous outrage over an exaggerated and unrepresentative portrayal?

New research from Gingerbread squarely challenges this line of defence. It shows around one in seven single parents receiving jobseeker’s allowance were sanctioned in a single year. To clarify, that’s over twice the monthly rate the DWP likes to quote. By using its monthly, rather than annual, figure the government is either relying on a lazy interpretation of its own data – or it’s deliberately downplaying the real risk of sanctions.

What’s more, single parents are now far more likely to be referred for a sanction (and have one imposed) than 10 years ago. What has changed? Has there been a surge in claimants flouting the rules? There’s certainly no evidence of this – the DWP would certainly be shouting it from the rooftops if there were.

If anything, the data shows a depressingly familiar picture, with single parents still more likely to be unfairly sanctioned than others. When formally challenged, the majority (62%) of their sanctions are overturned – a higher success rate than other claimants. This was the case three years ago, and it remains true today. As Gingerbread knows from calls to its helpline, single parent sanctions are often a result of over-zealous referrals and administrative errors. But there’s also a fundamental problem with the system itself, where advisers are forced to apply rigid rules regardless of people’s intentions or circumstances.

It’s easy to focus on the most outrageous cases, such as the single parent told to sign on or risk a sanction despite being on the way to an emergency hospital visit. Yet there are many more mundane examples – missing appointments by minutes, not recording information precisely as requested despite seeking work, not taking up a job interview because of a lack of childcare – where people have no intention of breaking the rules, yet are penalised financially. For single parents, the risk is particularly great. Juggling caring for children alongside job-seeking commitments often throws up demands and emergencies that need understanding, not judgment.

All this is justified in the name of getting people into work. But a recent report from the public spending watchdog, the National Audit Office, shows the DWP knows little about the actual impact of its sanctions policy. From what claimants tell us, it’s hard to see how the current approach is helping. Instead it risks pushing out-of-work families further into poverty without making work any closer a reality. When last month’s figures showed a spike in child poverty for single parent families, with nearly half of children in single parent families now living below the poverty line, that’s a policy choice that needs urgent questioning.

But a radical rethink seems a distant hope. For all its talk of a new approach to help out-of-work families, the government has had little to say on sanctions. In fact, reforms are set to spread the tentacles of sanctions even further.

Just last week, the DWP went ahead with reforms making single parents seek work earlier than before, and placing them at risk of sanctions if they don’t comply with rules. Around 165,000 single parents of three- and four-year-olds will now be expected to find work, despite childcare being at its most expensive and flexible local jobs being thin on the ground.

In other words, for the first time JSA sanctions will now affect pre-school children too. And that’s before we get to the conditions expected for low-paid working parents under universal credit.

Sticking doggedly to the line that sanctions are necessary is a simple and effective tactic from the government, but it’s one that favours political convenience over effective policy. It ignores the unfair and disproportionate rules that don’t reflect the realities of job-seeking. It ignores the overstretched and undertrained advisers behind poor decision-making. It ignores a proper assessment of whether what it spends its money on actually makes any difference – other than making those with little even worse off. And unless the government reflects on the mounting evidence of the punitive sanctions system, more and more single parents will have to say: “I, too, am Katie Morgan.”