A rollercoaster crash which seriously injured a number people, including two people who underwent leg amputations, was the result of human error when an operator manually overrode the ride safety system, it was revealed today (24 November).

The investigation did not find any technical or mechanical problems with the ride itself.

The finding was announced as Alton Towers completed its investigation into the Smiler incident that took place on 2 June at the UK theme park. The crash happened when a carriage full of people collided with an empty one, causing those in the front seats to suffer severe injuries.

A statement from Alton Towers said: “The investigation concluded that the incident was the result of human error, culminating in the manual override of the ride safety control system without the appropriate protocols being followed.”

The Smiler rollercoaster will re-open in 2016, Alton Towers said, and will be equipped with new safety features, including technical improvements. Staff will also be given additional training.

The park said it will add further protocols to the manual override process so that a senior staff member has to authorise and action the decision. The park said additional surveillance cameras and additional staff inspection checks will be put in place.

“Alton Towers continues to provide help and support to all of those who were on the ride when the incident happened,” the statement said. “It has taken full responsibility for the incident and continues to cooperate with the ongoing Health and Safety Executive (HSE) investigation. We are confident that lessons have been learned and that appropriate action has been taken to address all the issues raised by our investigation and we believe our core conclusions will be in line with the HSE findings.”

The park was closed for several days following the incident, and this along with the weak summer attendance in the wake of the crash caused profit losses to parent company Merlin Entertainments of around £50m (US$77.6m, €70m) and the loss of 190 jobs.

A spokesperson at Merlin told Attractions Management that the company is making no further comments at this time.