Its report into child inequality in 24 developed countries found that income poverty has the greatest impact on child inequality in the UK.
This is leaving the UK lagging behind other European countries such as France and Germany in improving the lives of the most disadvantaged children.
This latest report is released the same day as the government's poverty tsar Frank Field released his report into tackling poverty. This instead called for government policy to focus on investment in early years education.
Unicef UK executive director David Bull said: "Tackling income poverty should remain the number-one priority for government to reduce child inequality in the UK. At a time of austerity we must not widen this gap.
"One of the most disturbing aspects of changed economic times is that full-time employment no longer guarantees a life lived above the poverty line."
Called Report Card Nine: Children Left Behind, the report measures how far children in poverty have fallen behind in terms of health, education and material wealth.
Overall, the UK was ranked in the bottom two-fifths of countries, alongside Hungary, Slovakia and the Czech Republic.
Other recommendations are for the government to set "ambitious" interim targets in next year's child poverty strategy and apply a fairness test to changes to benefits and education.
The universal credit the government plans to bring in as part of reforms to the benefit system must ensure that no family lives on less than a living wage, Unicef added.
Register Now to Continue Reading
Thank you for visiting Children & Young People Now and making use of our archive of more than 60,000 expert features, topics hubs, case studies and policy updates. Why not register today and enjoy the following great benefits:
What's Included
-
Free access to 4 subscriber-only articles per month
-
Email newsletter providing advice and guidance across the sector
Already have an account? Sign in here