A COACH with 26 children and three adults from Barrow on board overturned on the M6 on Wednesday morning between junctions 34 and 33 at Lancaster.
The coach was travelling south on the motorway carrying youngsters a trip from West Shore Senior School at Walney.
Police closed the motorway in both directions and asked people to avoid the area.
One teacher and 15 'walking wounded' children were taken to the Royal Lancaster Infirmary for treatment with other casualties rushed to the Royal Preston Hospital.
The injured include a 72-year-old man - believed to be the coach driver - with a suspected head and rib injury, a pregnant teacher and one woman with non-serious arm injuries.
The coach overturned a few hundred yards away from Lancaster University at the bottom of University Hill on the motorway.
It came to a halt on its side across all three lanes of the M6 with the shattered glass testament to the severity of the crash.
A fleet of ambulances and the North West air ambulance had raced to the scene after the coach, one of three taking 12 and 13-year-olds on a day out to Southport, overturned and skidded down the motorway.
All the children had been led from the coach by the time emergency services arrived at the scene.
As temperatures soared to 34 degrees Highways Agency staff, paramedics and police officers delivered bottles of water to motorists stranded on the M6 in the aftermath of the crash.
Traffic tailed-back five miles to junction 34. Sweltering drivers sat on the hard shoulder looking on in disbelief down the carriageway at the scene of carnage as the overturned coach lay stricken on its side.
Miraculously, everyone on board the vehicle escaped with relatively minor injuries.
The crash caused major disruption at junction 34 on Caton Road, in Lancaster, while the city centre became gridlocked with southbound traffic diverted off the motorway and through the historic centre.
Chief Inspector Tracie O'Gara said: "It was remarkable that nobody was more seriously injured. Police were quickly on the scene to help the casualties and once we had made sure that all had been done to get them to hospital, we turned our attention to those who were stuck in the traffic.
"It was quite obviously a very hot day and we were able to get water and a little food to those that needed it and medical help was on hand in case anybody was suffering any ill-effects from the heat."
The vehicle - which was fitted with seat belts - will be subjected to a thorough examination by officers from both the police Accident Investigation Unit and the Vehicle Operating and Services Agency.
The motorway was closed for just under four hours, while the casualties were removed, the scene examined, vehicle recovered, and carriageway repairs affected.