The Association of Metropolitan Authorities' study, Children and Trouble, also criticised 'massive' regional variations in sentencing young offenders. Cautioning rates varied from 49 per cent of boys aged 14-16 in Durham to 84 per cent in Kent.
The report comes amid demands for a crackdown on teenage crime, with the Government considering establishing secure units to give persistent offenders aged 12-15 a regime of punishment, discipline and education.
A survey of police forces found a hard core of between 100 and 300 young criminals, but Home Office officials believe that underestimated the problem.
The new report argues that while arrest figures are difficult to interpret, it appeared that juvenile crime was 'no longer out of control', with a 40 per cent drop in youth crime between 1979 and 1990. But the number of crimes was growing, with a rising number of persistent offenders.
Last year, young criminals in West Yorkshire were responsible for 21 per cent of crime, although they are just 10 per cent of the population. National statistics in 1990 showed nearly a quarter of crime was committed by a juvenile population of 10 per cent.
Sandy Marks, chair of the AMA working party which prepared the report, said there had to be a speedier system to stop young offenders early in their criminal careers. The issue was about community safety and preventing youngsters from continuing to offend to ensure crime was reduced.