Highways England warned that police are currently responding to reports of youths on the M1 between Junction 39 and Junction 40, and that young people on the road is a 'massive problem' over the summer holidays every year.
A spokesman said: "M1 J39 to J40 #TrafficOfficers & Police are responding to reports of youths on motorway.
"Its a massive problem for us at this time of year. #SummerBreak Have a chat with your child about #Safety. Motorways are dangerous."
It's illegal for pedestrians to use the motorway at any time.
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