BREXIT may get all the headlines, but for millions of Britons another change is looming which could have an even bigger impact on their lives. By 2022 the government hopes to have fully implemented “universal credit”, the biggest shake-up of the welfare system in decades. One in four households will receive payments under the new regime. Many aims of the scheme are laudable. But it is plagued with problems that could spell trouble for its recipients—and for the government.

Recent administrations of left and right have reformed welfare to make work pay. Today Britain has one of the rich world’s highest working-age employment rates, at around 75%. In America, whose rate is more like 70%, those on the political right often say that Britain has shown the way. The Conservative government claims that universal credit, which merges six existing benefits—from working tax credit to housing benefit—into one, will nudge another 250,000 people into work.

Yet as it is gradually rolled out, universal credit is proving deeply unpopular. Bradford, a relatively poor city in northern England, will introduce it this month. At a benefits “summit” organised by community groups in a hall on the outskirts of the city, there is a palpable nervousness. Over onion bhajis, locals air their fears. One has heard that evictions have risen in areas where universal credit has been implemented. Another exhorts the assembled throng to “arm ourselves” with information to cope with the change. To understand why everyone is so anxious, consider how universal credit is designed, and how it works in practice.

Universal credit was conceived in the late 2000s as a fairly generous scheme that would establish the Tories as champions of the deserving poor, rather than the misers many working-class voters believed them to be. Yet over time, the government came to see the new system as a way to save money. George Osborne, the chancellor in 2010-16, reduced the amount that claimants had to earn before their benefits were withdrawn. The upshot is that universal credit is expected to end up being about £2bn ($2.7bn) less generous overall than the previous (already hard-nosed) system, shaving around 3% off the total bill.

One of its appeals is its apparent simplicity. Rather than having to supply personal information again and again to different government bodies, in theory claimants need do so only once, points out David Finch of the Resolution Foundation, a think-tank. By merging six payments into one, claimants are less likely to miss benefits to which they are entitled. Simplification also removes some of the perverse incentives of the old system, under which some claimants faced marginal tax rates of up to 100%.

Yet this simplicity also has downsides. Take the way that universal credit is paid. Claimants generally receive a single payment once a month. That arrangement rationalises what was a mish-mash of disbursements under the old system. It also mimics the way that most employees are paid. But over a tenth of employees are paid weekly, and the share is higher among low earners, who are most likely to receive universal credit. Reams of research show that people on low incomes struggle to budget over long periods. A recent official memo points out that “[f]or some claimants this change of payment frequency on transition to UC has been challenging and [has] led to rent arrears.”

Claimants also appear to be struggling with the conditions attached to receiving benefits, which have been tightened for many people under universal credit. As of early 2018 about 4% of universal-credit claimants were being “sanctioned” for breaking their commitments, resulting in a lower payment. David Webster of Glasgow University suggests that the sanction rate for unemployed universal-credit claimants is about twice that under the old unemployment benefit.

However, the biggest problem facing universal credit has been poor implementation. Claimants generally must wait for five weeks before receiving their first payment, as employees often do when they start a new job. Plenty of those moving onto universal credit have practically no financial assets, making this a painful wait. And IT glitches mean that five weeks is often a minimum. Towards the end of last year the government revealed that 4% of claimants had not been paid in full even after ten weeks. Food banks report higher demand in areas where universal credit has been rolled out.

The upside to a tougher benefits system could be higher employment. Yet Paul Johnson of the Institute for Fiscal Studies, a think-tank, has said that the impact on employment is “highly uncertain”. Evidence so far suggests that it may be less impressive than the government hopes. Our analysis finds that the employment rate in areas where universal credit has been introduced has grown no faster than in areas where it has not. Joblessness is already very low; the minority that cannot find work probably require intensive training rather than changes to the way that benefits are administered.

With universal credit being rolled out bit by bit, the government can adjust the scheme as it goes along. In the budget in November, Philip Hammond, the current chancellor, bumped up the transitional loans to which claimants are entitled as they await their first payment. It is getting easier for claimants to have their money paid directly to landlords, so that they do not fall into rent arrears.

It is odd, though, that a government which is courting votes from the “just about managing” classes is not more sensitive to the upset its policy seems to be causing. Reducing the waiting period to a fortnight, say, would not cost much. Pausing the scheme to fix its administrative problems would be easy. Yet despite evidence suggesting it should change course or risk doing real damage, the government seems determined to plough ahead with a giant, increasingly unpopular project that will reshape the country. Sound familiar?