More than 1,000 children under the age of 10 are being subject to stop and search by police in England and Wales over the last five years, according to a parliamentary report.
Across 22 of England and Wales' police forces, 1,136 children were searched despite being under 10, the age of criminal responsibility.
The figures are revealed by the All Party Parliamentary Group for Children.
The report said the data collected suggested that stop and search was used "disproportionately" on black and ethnic minority children and young people.
Over the same period, over one million stop and searches were carried out on children and young people under the age of 18 across 26 forces, which accounted for up to 28% of all stop and searches undertaken by the forces.
The total of 1,136 children under 10 excludes figures for the Metropolitan Police, the largest police force. The Met could not provide full figures for the period 2009 to 2013, but said it recorded 136 stops between 2011 and 2013. Six of those stops involved children under five.
The report shows that of the 43 forces that provided data for the inquiry, 20 did not have separate custody facilities for children and young people. It said holding children alongside adults potentially exposes them to harm and distress.
The Association of Chief Police Officers said a "recording error" had led to an inaccurate figure, according to the BBC.
Across England and Wales, police forces told the parliamentary inquiry that it was necessary to stop and search under-10s because they could be used to conceal stolen goods or drugs.
Head of national policing for stop and search, Cdr Adrian Hanstock, said: "In the genuine cases, children are often stopped because of intelligence that they are being exploited by adults, including gang members, to carry drugs, weapons or get involved in other criminal activity."
Last week, police in Scotland announced they would no longer subject children under 12 to "consensual" stop and searches.
Lady Massey of Darwen, who chairs the parliamentary group, said: "We were surprised to find that despite the fact that so many children are being stopped and searched by the police, there is no practical guidance to inform how to deal with children, particularly those who are young and vulnerable."
She added that many of the children stopped could be fleeing sexual or gang violence and were likely to be in need of care and protection. "The police need to be sure they do not see children as small adults and do more to ensure they always adopt an age-appropriate response to every child," she said.
Enver Soloman, of the National Children's Bureau, which runs the inquiry's secretariat, said: "The inquiry is shining a light on how the police interact with children and finding that there is a need for a new approach. Any child who comes into contact with the police should always be treated differently from an adult."