The victims, three of whom are teenagers, were crushed when their roller coaster carriage careered into an empty one on the Smiler Ride at Alton Towers.
It took a total of five hours to cut all the passengers free from the wreckage on Tuesday - where two people were left hanging upside down, 25ft in the air.
Witnesses to the crash said they heard an ‘almighty bang’ before seeing ‘blood everywhere.’
The Smiler Ride opened in 2013 but has been dogged by faults since it’s opening - and on Tuesday had been having problems all day.
Workers on the ride sent out an empty carriage to test it, followed by a full carriage of customers.
‘People were screaming and crying’ said an onlooker. ‘Suddenly the carriage moved - almost as though staff hit the wrong button - and it went down the loop and then smashed into the empty carriage.’
‘It was horrendous. The impact was massive and the people at the front looked unconscious for a bit.’
‘The carriage was crushed at the front and they must have suffered leg injuries.’
Now a staff source is claiming that one of the injured parties has lost a leg in the incident.