Thousands of children are being "needlessly dumped in prison" because of Britain's failing youth justice system, a think-tank has warned. The Centre for Social Justice (CSJ) said courts and prisons were being used to "parent children" and were expected to sweep up problem youngsters inadequately dealt with by other departments, such as social services. In a new report, the group called for a radical overhaul in the way the Government deals with young offenders. It said there needed to be a drastic cut in the 5,000 children a year currently given custodial sentences, arguing the imprisonment of youths between the age of 10 and 17 should be limited to the "critical few" guilty of the most serious or violent crimes. The CSJ said too many children are being taken before the youth courts for trivial reasons. The report cited one example where a child who had thrown a bowl of Sugar Puffs at his care worker, jumped out of the window, then climbed back in, was held in a police cell over a weekend on suspicion of assault and attempted burglary. The independent think-tank, set up in 2004 by Work and Pensions Secretary Iain Duncan Smith, urged a return to a "common-sense" approach to minor incidents with parents and teachers using their judgment to deal with them at a home or school level. It also criticised the widespread use of short sentences for young offenders, arguing they undermine justice and disrupt attempts to educate and rehabilitate them. Gavin Poole, executive director of the CSJ, said: "Many young people fall into the system unnecessarily and do not receive the help they need to free themselves from it. Custody is sometimes neither a protective nor a productive place for children, and community orders can be equally ineffective. Moreover, despite years of good intentions, many young people leaving custody are still not being provided with the basic support they need for rehabilitation." Among a series of recommendations, the CSJ said there should be no sentences shorter than six months and an emphasis should be placed on non-custodial punishments where underlying behavioural problems can be tackled more effectively. The group also said measures to prevent lawbreaking by young people should be the primary responsibility of child welfare services rather than the youth justice system. It added local services needed to work together to ensure that young people and their families receive the help they need early.