There are half a million children in the UK who are unhappy with their lives, according to a report out today.

The Good Childhood Report 2012 was launched today by the Archbishop of York, Dr John Sentamu.

It warns that a generation of children will be “lost” unless a radical new approach is taken to childhood in Britain.

The report was compiled by the Children’s Society and is based on interviews with more than 30,000 children aged eight to 16.

Nine per cent of children across the UK are identified in the report as having “low wellbeing” – a percentage that equates to 500,000 children.

The report found a significant increase in levels of unhappiness as children get older. While 4% of children aged eight had low wellbeing, this figure rose to 14% among those aged 15.

The family has the biggest influence on levels of happiness, with children more likely to feel happy if there is harmony in the home and if they have an experience of loving relationships between family members.

Children who felt listened to and involved in making decisions within the family also had a “significantly” higher level of wellbeing.

The home environment was found to be important in giving children a sense of safety, with those who had experienced more than one change of home in the past year more than twice as likely than average to have low wellbeing.

Children in the poorest 20% of households were also found to have “much lower” wellbeing than average, as were children who felt they had much more or much less than their friends.

Image was also found to be a factor. While only a quarter of 10-year-olds cared about their appearance, by the age of 15 this rose sharply to 32% of boys and over half of girls (56%).

Girls were especially likely to feel that they did not fit in if they were not wearing the right clothes.

The report identifies six priorities for a happy childhood as ensuring: the right conditions to learn and develop; that children can develop a positive view of themselves and a respect for their identity; that they have enough of the items and experiences that matter to them; have positive relationships with their family and friends; and a safe and suitable home environment and local area.

The Archbishop of York said: “The moral test for any society is how it treats its most vulnerable, including its children. The fact that at any one time half a million children who are unhappy with their lives should be a wake-up call to us all."

Elaine Hindal, the Children's Society's Campaign for Childhood Director, said: “We are calling for a radical new approach to childhood, placing their well-being at the heart of everything we do. Our research has exposed that how children feel really matters.

“We know that, right now, half a million children are unhappy. We have discovered the key reasons for this unhappiness and what we can do to make it better. We want our country to be the best place for our children to grow up.

“Yet unless we act now we risk becoming one of the worst and creating a lost future generation.

“The charity has created a new, comprehensive way of measuring children’s wellbeing. We urge government and other decision-makers to use the six priorities we have pinpointed. This is a real opportunity to make a huge difference to their lives.”