The publication of the Joseph Rowntree Foundation’s annual report into poverty makes for sober reading. Despite being one of the wealthiest countries in the world, the JRF says there are now over four million children growing up in poverty in the UK. Their analysis shows that in the last five years poverty rates have risen for every type of working family – lone-parent or couple families, families with full and part-time workers and families with different numbers of adults in work. This is the first period in the last two decades when this has happened, and it is happening at a time of rising employment. A working parent is now over one-and-a-half times more likely to be in poverty than a working non-parent. The report follows the recent critical UN investigation which concluded that poverty is causing ‘misery’ for millions of families.

As Children’s Commissioner for England, I meet children from all sorts of backgrounds. Some of the children I meet from the poorest parts of the country are doing well and it would be wrong to say every single child growing up in poverty is unhappy or at risk. But the evidence is clear – if you grow up in poverty you have less chance of living a healthy, prosperous life. Alongside the day-to-day anxieties about finances, the strained relationships within families and missing out on many of the childhood experiences other children enjoy, there can be big long term consequences to growing up in poverty. A child living in poverty is more likely to lag behind at school and to leave the education system with poorer qualifications and lower ambitions. They are more likely to struggle to find a well-paid job with good prospects and they are also more likely to suffer from health problems later in life, and die at a younger age.

So eliminating child poverty should be a moral endeavour for every government, regardless of its political persuasion. Overcoming poverty is a challenge, but that doesn’t mean it can’t be done. Previous policy interventions have shown that governments can lead the way in reducing child poverty, in particular providing help to working families in low paid jobs. This is not happening at the moment. If anyone is in doubt, spend a few hours at your local food bank (there will likely be one, wherever you live) or talk to the teachers in the growing numbers of schools with washing machines and clothes banks for families. Millions of families are working night and day just to get by, juggling their childcare between them, and ending up with hardly anything to show for it. How can it be right for a third of children in every classroom to be poor? Anyone who thinks this is acceptable needs to seriously think again.

I remain very concerned that recent changes to the benefits system, including the move to Universal Credit (UC), are having the opposite effect of their original intentions – with devastating consequences.

Over the last two years, an increasing number of parents and professionals have raised with us their concerns about Universal Credit. Their stories paint a picture of a system beset with complications and flaws, which is often putting enormous stress and strain on families, some of them already on the verge of crisis.

It’s important to remember that UC is being introduced in the midst of a number of wider changes in the benefits system which are disproportionately affecting families with children. 93% of households affected by the benefit cap are families with children, and according to the Department of Work and Pensions’ own numbers, the overwhelming majority of people affected by the benefit cap are single mothers, frequently with young children.

There have been other benefit changes targeting children: between 2009/10 and 2019/20, the value of child benefit will fall by 17% in real terms. This comes at the same time as the value of the state pension will rise by 54%. More evidence that governments can have an impact.

However, instead of redressing these changes within the benefits system, UC keeps all the changes to the “legacy benefits system” and adds some further cuts aimed at working families with children. By 2020, just the changes announced since 2015 will mean the poorest 10% of families will be 15% worse off.

Our recent IFS report shows that benefit spending per-child will fall 17% in real terms betweejn2009/10 and 2019/20, and that most of these cuts will only bite once families transfer from “legacy benefits” to UC. Research from the Resolution Foundation suggests that Universal Credit will pay out nearly £3bn less than the Tax Credits system it replaces and that most of these cuts will be borne by families. The upshot is that poverty rates amongst children are already higher than amongst other groups of the population and are set to increase relative to other groups.

There is no doubt that for both new claimants and those on ‘legacy benefits’ who will transfer the system is complex and is causing severe problems. Many of the most vulnerable families are understandably struggling to navigate their way around these complexities and as a result can go for long-periods without money. From our own conversations we know that the result of this can be parents struggling to feed their children.

All of the UK Children’s Commissioners can tell the same story. That’s why last year we came together to call for the roll-out of UC to be halted until a proper impact assessment is undertaken into its effect on families. That still stands. We should not be forcing some of the most vulnerable families into using a system when we don’t really know what the impact will be.

There is no doubt in my mind that the biggest losers under Universal Credit are families with children, especially single parents. The Government have never fully justified this and there is no clear rationale for making children the losers when they already have higher levels of poverty.

Clearly no child should be worse off under UC and I hope the new Work and Pensions Secretary will take this opportunity to look again at what is happening and stop the roll out until its impact is assessed properly and that guarantee can be given. At a time when millions of children in Britain are already living in poverty, as today’s Joseph Rowntree Foundation report highlights, the least we can do is have a system that does not push those children even further into hardship. On taking up her new job as Secretary of State Amber Rudd said that she was prepared for straight talking with the Treasury if more funds were needed to help poor families thrive. That’s a conversation that needs to happen now.

The number of children in poverty in our country should shock every politician into action. We need to halt UC until children’s welfare can be guaranteed and to reverse the benefit changes that have had a negative impact on children. And we need to put in place programmes that offer early help and family support – Sure Start or family hubs that aim high and help those families to overcome the poverty that traps and limits so many aspects of their lives. If we don’t, we are denying millions of children the support the need and denying them a fair chance in life.

Anne Longfield is the Children’s Commissioner for England