There are two very different types of means-tested benefit affected by the change to the rules about uprating. Some benefits – mainly now Jobseekers Allowance, and Employment and Support Allowance – are income replacement benefits, which provide a minimum allowance. Those benefits used to be uprated in line with inflation; they were then set to be uprated by a different, lower measure of inflation, the CPI; and now they are not going to be uprated with inflation at all, which means they are being cut in real terms. The other class of affected benefits are the income supplements – mainly Housing Benefit, Child Tax Credit and Working Tax Credits (the impact on Council Tax Benefits is still difficult to gauge, because that’s being taken out of the national system). These benefits are based on a calculation. There’s a starting figure, at which full benefit is paid, and then a taper which leads to the benefit being reduced as income increases. The change to the uprating rules affects the starting figure, so a change in the basis of uprating will lead to someone on a constant income getting lower benefit than they would otherwise. The calculation is complex, however, and because this interacts with tax, national insurance, rent and wages, there isn’t a one-to-one correspondence between the percentage of the uprating and the amount of benefit lost.
The opposition to lower upratings has, rather oddly, focused on the second group of benefits, where it’s much more difficult to show that the cut will make a big difference. That’s probably because the minimum income benefits go to groups that are stigmatised and hated. “Rage”, Janan Ganesh writes in a thoughtful piece on benefits for the Financial Times, “is rarely forensic”. If you’re a middle-class voter, ironically, you’re probably more likely to be vulnerable to unemployment or disability than you are to move to a low wage or rented accommodation. So the benefits which are being most directly undermined are the ones which are most important for social protection.