Police have reprimanded three boys aged between seven and nine for throwing lumps of concrete and tree branches at vehicles on a major road in Essex.
The youngsters were caught throwing objects at fast-moving traffic on the A12 near Colchester after six of the drivers made emergency calls.
No-one was injured in the incident, but one of the concrete blocks hit a lorry while motorists had to drive around the debris.
A police spokesman said: "The boys were standing on the verge behind the barriers and throwing objects as vehicles approached. The road was busy at the time and traffic was fast-moving.
"We were amazed at the size of the concrete blocks and branches. They could have caused serious damage."
Inspector Steve Brewer added: "If the culprits had been aged over 10, the age of criminal responsibility, we would have taken a more formal approach."
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