The head of the influential House of Commons home affairs committee says he is "deeply concerned" at an investigation showing children as young as four are being treated for drug and alcohol misuse.
Labour MP Keith Vaz called on parents to do more to prevent risks to their children.
"It is right that these youngsters receive the appropriate help but we must look at the source of their problems," he said.
"It is vital that parents take responsibility and additional support is given to them in order to prevent children being exposed to drugs and alcohol in the first place."
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