Britain has been criticised by the UN, after new research reveals it is lagging behind much poorer countries on reducing inequalities between rich and poor children.
The Unicef report, Fairness for Children, strongly suggested the government should reconsider its cuts to benefits.
The UK ranked 25 out of the 37 wealthy countries included in the report, below Romania, Slovenia and Poland, for its equality levels in children's reading, maths and science skills at 15.
When it came to the impact social backgrounds had on the healthy behaviours of children, including consumption of fruit and vegetables, the UK was ranked bottom.
It also ranked low concerning physical activity.
"Inequality between children is damaging their lives and aspirations" in the UK, said Lily Caprani, Unicef's deputy executive director for the UK.
"Taking children's rights seriously means acting with urgency to make sure no child is left behind."
The measures of inequality were taken from a survey on health-related activities and educational acheivement data from EU and OECD countries.
"The UK government should adopt, as a matter of urgency, a childhood obesity strategy that promotes and supports healthy lifestyles for low-income children," said Caprani.
"It must also act to further reduce income inequality, which includes protecting social transfers [benefits]."
The government had pledged that the budget for welfare would not be reduced this parliament, however it is still committed to £3 billion in welfare cuts which will affect one million households by 2020.
Owen Smith, Labour's Shadow Welfare and Pensions Secretary, said: "For anyone who wants our country to be the best place in the world for children to grow up, this report will make depressing reading.
"Tory cuts introduced this week to Universal Credit will undermine that progress, leaving a working single mother £3,000 a year worse off, while over time resulting in over two million working families losing an average of £1,600 per year, driving up child poverty," he added.