Sixteen people have been injured, four seriously, in a rollercoaster crash at Alton Towers.

The theme park said that first aid staff were on the scene and emergency crews were building a platform to help reach the stranded riders.

The accident happened when a carriage carrying 16 passengers on the Smiler ride crashed into a stationary empty carriage.

Eyewitnesses reported hearing screams as the carriage turned the corner and the passengers saw that they would not stop in time, followed by a loud crash.

Ben Rochardson, who was at the seen, captured a photograph of the scene

Smiler coasters have just crashed! Watch this space. #Altontowers #gotwhiplashwatching pic.twitter.com/xYRMRO9h7I

— Benj (@_ben_jamming) June 2, 2015

The ride had been delayed due to a technical fault, before staff sent an empty carriage around the track. The carriage that crashed was the first carriage to travel along the track with passengers after the ride re-opened.