A survey conducted by the NSPCC has found that nearly one in five secondary school children in the UK have been severely abused or neglected.
The study was carried out in 2009 and follows on from an earlier NSPCC survey of the childhood experiences of 18-24 year olds in 1998-99.
The research found that one in five 11-17 year olds - or 973,000 children - had been physically attacked by an adult, sexually abused, or severely neglected.
On a more positive note, the charity also found some types of abuse had fallen over the last 30 years, which the NSPCC says shows progress can really be made in the fight against child cruelty.
Andrew Flanagan, the charity's chief executive said: 'Our research shows that many children are now treated less harshly than previous generations. We believe that heightened awareness and action has contributed to changing public attitudes and behaviours towards children for the better.
'The NSPCC is calling on people to be vigilant to the signs of abuse and call our 24-hour Helpline if they are concerned about a child. And we urge children themselves to contact ChildLine whenever they have a problem.'
The NSPCC has issued advice on how to spot the signs that something might be wrong:
· Is the child self-harming or suicidal?
· Is the child anxious or depressed?
· Is the child showing signs of delinquency?
· Does the child spend time with their family?
· Do they seem to have a good relationship?
· Is the child left at home by themselves?
· Are they left out late at night?
· Is their home clean and tidy?
· Does the child seem dirty or smelly?
· Are they bruised or cut in any way?
If you are worried about a child you can call the NSPCC's a free, confidential, 24-hour Helpline on 0808 800 5000
If a child needs to talk about something that is worrying they can call ChildLine on 0800 1111