Childhood is supposed to be the happiest time, but for a quarter of a million girls - one in seven in the UK - life, as our Good Childhood Report reveals, is unhappy.
The picture is even starker when it comes to how girls feel about their appearance. A shocking 700,000 said they feel unhappy with how they look.
It is desperately worrying that so many of our young people are suffering rather than thriving and it is clear that concerted action is needed to tackle this problem.
For the last 11 years The Children's Society has been asking 10 to 15-year-olds across the country how they feel about their lives. Disturbingly, a gap between girls and boys has developed in recent years, with girls becoming increasingly unhappy with their lives overall and with their appearance. Over the last five years, the situation for boys has remained stable.
The increase in social media, growth in celebrity culture, exam pressures and the expectations of friends and family may all play some part in this alarming trend. But the truth is, the scale of this problem goes well beyond that and the Government really needs to take this problem more seriously. It needs put more money and resources into investigating what's behind this.
Alarmingly we found that about half of all children in this age group have been bullied at school in the past month. Emotional bullying, such as name-calling which is more prevalent among girls, is twice as common as physical bullying, which is more likely to affect boys.
The effects of using social media are also a cause for concern. Research suggests that girls are much more likely to spend extended periods on social media, which has been linked to a higher risk of mental ill-health.
Through this annual survey, we have found that there is a clear link between unhappiness and mental health problems. Boys and girls experience mental health problems in different ways. While 10 and 11-year-old boys are less happy with their school work than girls and are more likely to experience problems with hyperactivity and their conduct, girls suffer anxiety and depression significantly more than boys and become increasingly unhappy with their appearance as they get older.
It is crucial that the Government takes action to improve children's happiness across the nation. By introducing a legal entitlement for children to be able to access mental health and well-being support in schools and FE colleges across England and Wales and reaffirming its commitment to understanding, measuring and acting to improve children's well-being, this downward trend in happiness can be reversed.
Local authorities also have a role to play. Children's perceptions and experiences of their local area, including how safe they feel, their sense of freedom and how they view the quality of facilities are clearly linked to how happy they feel. Local authorities need to listen to children's views about what matters to them and make sure they are directly involved in decisions that are made about their local areas.
All children deserve a happy childhood and we must never accept that it is somehow inevitable that so many children in this country should live in distress. Children must be heard and helped.