The number of annual arrests of children under ten has collapsed over the last five years from around 800 to just 23.
Statistics released by Home Office minister Damian Green showed an even bigger collapse in the number since 1999/2000, when 1,200 arrests of under-tens were registered.
In 2006/07 this halved to 446 arrests before falling to 163 in 2007/08 and just 23 by 2010/11, the government confirmed.
Experts have struggled to explain the collapse in the numbers, which were revealed following a question from shadow justice secretary Sadiq Khan.
His parliamentary question, which prompted the release of the government statistics, showed a marked fall in the number of arrests of those aged between ten and 17 over the same period.
There were 319,600 arrests of those aged under 18 in 1999/2000. This number had fallen to 210,683 by 2010/11, broadly in line with the 40% drop in crime achieved over that period.
Peter Cuthbertson of the Centre for Crime Prevention thinktank commented: "These figures reflect a fall in offending, but youth crime remains a major problem and police are right to take it seriously.
"Nearly all of these 200,000 arrests were for serious crimes like violence, theft and burglary. It is vital for public safety that strong punishment follows arrest for young thugs."
The Home Office did not offer its own interpretation of the figures for under-tens, however, which represents a fall in the number of arrests of 98%.
Khan claimed the credit for the overall decline, which he said reflected investment in intervention, diversion and joined-up working across central and local government.
"The Youth Justice Board – working with youth offending teams up and down the country – deserve credit for their hard work in preventing young people getting sucked into a life of crime, but also the way they punish and reform those who do offend," he said.
"The foolishness of the Tory-led coalition's plans to abolish the Youth Justice Board, only abandoned after fierce campaigning by Labour and others, becomes more apparent by the day."