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."
More top news
A teenage boy has been stabbed to death in London, the second fatal attack within two days.
A British amateur sailor died this morning after being hit by a sail while taking part in the Clipper Round The World Yacht Race.
Plans for seven-day GP services are "unrealistic" because of a shortage of doctors, the Government has been warned.