Campaigners have called for greater action to help raise living standards after the depth of child poverty was revealed in a study by the charity the National Children's Bureau, published today.
The report, marking the bureau's 50th anniversary, revealed 3.5 million children are growing up in poverty today compared to two million in 1973, and warns they will likely suffer devastating consequences throughout their lives, such as poor education and health.
In Scotland, the report suggests that one child in five children is living in poor housing, failing to eat properly and not achieving his or her full potential at school.
The study - entitled Greater expectations, raising aspirations for children - shows a child from a disadvantaged background is far less likely to achieve a good level of development at age four, or match those from better off backgrounds at school age 11.
Boys living in deprived areas are three times more likely to be obese than their counterparts in affluent areas, while girls are twice as likely to be overweight.
Children in deprived areas are also much more likely to be the victim of an unintentional injury or accident in the home, and are nine times less likely than those living in affluent areas to have access to green space and places to play and to live in environments with good air quality.
The report says that the UK is lagging behind other industrial nations when it comes to eliminating child poverty, and suggests that 770,000 fewer children under five-years-old would be living in poor housing, if conditions were brought into line with other developed nations.
Dr Hilary Emery, chief executive of the National Children's Bureau, said: "Our analysis shows that, despite some improvements, the inequality and disadvantage suffered by poorer children 50 years ago still persists today.
"There is a real risk that as a nation we are sleep-walking into a world of social apartheid, with poor children destined to experience hardship and disadvantage just by accident of birth, and their more affluent peers unaware of their existence."
The charity Children in Scotland, which is preparing a similar report for publication next month focusing on conditions north of the Border, said that the findings should serve as a wake-up call to Government.
Children in Scotland chief executive Jackie Brock said: "Here in Scotland, figures suggest around one in five children lives in poverty. This means one in five is living in poor housing conditions, is going hungry and is not achieving their full potential academically. This is one too many."
"We know there is an intrinsic link between inequality, disadvantage and children's outcomes in life. Poverty in Scotland has flat lined since 2010, but has not fallen, and this needs to change.
"We support the NCB's call to do more to tackle child poverty and inequality and will support our Governments in both the UK and Scotland in their measures to do so."
In other findings, the NCB report said that, while the UK has above average levels of participation in early years education, the country is still lagging behind France, Belgium and Denmark.
If the UK was on a par with those nations, the charity said 300,000 more young children under three, representing one-quarter of all children in that age group, would be accessing services to help them develop well.