In politics, there are some ideas that are good in theory but don’t work in practice. Then there are those that were always going to cause harm but turn out to be more damning than even the policy’s architects could have imagined. Increasingly, the benefit freeze is the poster child for the latter category. The government is rightly coming under increasing pressure to halt the roll-out of universal credit. But lifting this freeze in benefit levels should be as much of priority.

In the 2015 budget, then chancellor George Osborne put in motion a freeze on most working-age benefits for four years, from housing benefit and tax credits, to employment support allowance and child benefit. In other words, on the “top-up wage” for the mum working all hours as a care assistant but still struggling to pay the rent, or the safety net for the cancer patient temporarily too ill to hold down a job.

The freeze means huge chunks of the population suddenly unable to afford the weekly food shop or pay the rent

The human impact of a policy like this is obvious: when benefits don’t keep up with inflation, families already on some of the lowest incomes in the country are left struggling even harder to meet basic living costs. And because increases in inflation have been greater than expected, this freeze is biting harder than even the Conservatives imagined. Inflation will have eroded in real terms an estimated £0.9bn more a year from the budget by 2020 than ministers intended – and a staggering £4.9bn in total.

The result is huge chunks of the population suddenly finding they can’t afford the weekly food shop, to put the heating on in the winter, or pay the rent. Over the next year, 7.3 million children – that’s half of all families with children – will be hit by this freeze. And we can add to that 2.4 million disabled people. According to the Resolution Foundation, by 2018-19, families could be up to £315 worse off a year due to the policy. It will also mean a widening income gap between rich and poor, with a year-on-year fall in income for the lowest earners – for the first time ever.

By the time the freeze is scheduled to end in 2021, the Joseph Rowntree Foundation (JRF) calculates that almost half a million more people will be living in poverty as a result. To put that in context, that means the benefit freeze will be the single biggest policy driver behind Britain’s expected rise in poverty over the next four years.

That the majority of these families are actually in work feels like a particularly hollow joke considering the “shirkers v workers” ideology that underpins the benefit freeze. At the height of the Conservatives’ “hardworking families” rhetoric, the introduction of the benefit freeze spoke to the growing demonisation of social security and the people who rely on it. Osborne claimed at the time that freezing benefits would “make Britain fairer” – the implication being that, in the contest between “deserving” workers and “undeserving” welfare claimants, freezing benefits would somehow push things in the former’s favour. It was a nasty divide-and-rule tactic: perpetuating the false ideas that benefit claimants are skiving off employment - when many of them are actually in low-paid work - and that the best way to ensure work pays isn’t to raise wages, but to cut benefits.

A couple of years on, while the language around welfare has changed, the drive to shrink social security is as strong as ever. The Child Poverty Action Group and the Institute for Public Policy Research thinktank found this week that families are being left thousands of pounds worse off a year due to continual benefit cuts. After all, the benefit freeze isn’t happening in isolation. The same people having their benefit frozen are likely also facing direct cuts to levels of universal credit work allowances, tax credits, and disability or housing benefits.

Families thousands of pounds worse off after years of cuts, study finds Read more

Things are only set to get harder. The uncertainty of Brexit will likely further impact families living without economic security: the National Institute Economic Review warned this week that households will have to find up to £930 more a year for basics like meat, vegetables, and clothes if Britain walks away from Brexit talks without a trade deal, with poorer families with children and unemployed people the worst hit. Even without taking into account Brexit, the JRF calculate that by 2020, a decade of benefits not keeping up with prices means low-income families will have lost the equivalent of about a third of their annual shopping bill, whilst Shelter warns more than a million households could be forced out of their homes by then if the housing benefit freeze remains in place as planned.

The JRF calculates that if the government ended the freeze early it would prevent almost 400,000 fewer people from being in poverty in 2020 – the majority of those being working families or those with children. And just lifting the freeze in universal credit, while increasing child benefit in line with inflation, would result in 300,000 fewer children in poverty.

It’s easy to lose sight of the fact that behind each number is a real family – one falling into hardship at the hands of outdated, rotten government policy. If Theresa May’s ever-weakening government has any desire to help her “just managing families”, they’ll use this month’s budget to lift the freeze on benefits. If not, it simply underlines the extent to which the Conservatives – fully aware that inflation has made the effects of the freeze have been made even more pernicious than expected – are simply abandoning people without enough income to live on.

• Frances Ryan writes the Guardian’s Hardworking Britain series