The incredibly dangerous manoeuvre was performed by the driver of a BMW saloon in lane one of the southbound carriageway near junction 16.
Dashcam video footage shot from the car of the astonished motorist shows vehicles having to take evasive action to avoid ploughing into the boy and the BMW, which had a male driver and a woman passenger.
Unable to overtake due to constant traffic to his right, the car with the camera has to come to a complete halt behind the BMW - placing its driver in a vulnerable position.
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The driver, who sent his footage to the Chron, said: "I've had to stop in a live lane of the motorway behind this mindless idiot.
"What I saw was beyond complete belief and could have easily resulted in a serious injury or even death. I was afraid the cars behind me wouldn't be able to stop in time."
The BMW then leaves the scene, driving past a turn-off for motorway services just 50 seconds later.