Of the 560,445 children helped between October 1986 and March 31, 1996, 77,425 called about sexual and 74,605 about physical abuse.
Abusers were mainly relatives, but reported abuse by natural fathers has dropped. Most of the original callers had been abused for at least a year but now 40 per cent of sexually-abused children who call ChildLine do so within weeks.
However, the total number of children who called last year because they were abused was 59 per cent up compared with 10 years ago at 16,745.
The number of children calling to report bullying rose from 3 per cent in 1986 to 12 per cent last year. British Telecom estimates that up to 10,000 try to call ChildLine each day, but at present the charity can only answer 3,015 of those calls.
Esther Rantzen, founder and chairman of ChildLine, said: "ChildLine counsellors help them, wherever possible, to identify a trusted adult in whom they feel able to confide. Some of the most distressed children are desperate to stay anonymous because they have been threatened. An abusing father told his daughter he would kill her mother if she told anyone what he was doing. Another said he'd kill his daughter's cat."