'We've never had an accident like this' - Company CEO speaks

In the wake of the roller coaster crash which happened at Alton Towers leaving 4 people seriously injured, a footage of the incident has emerged.

In the video, the 16 people on board The Smiler ride were seen rocking backwards and forwards, after the carriage they were travelling in collided with a stationary carriage.

Meanwhile, Alton Towers has released a statement saying it is "currently making contact with the families of all those involved and will continue to communicate with them."

Yahoo News reports that staff were quick to evacuate the area following the accident, which left four people with "significant lower limb injuries"  and the amusement park has been closed until at least Friday as an investigation continues.

Meanwhile reports say the company which owns and runs Alton Towers has said it's an accident which shouldn't have happened as there should be failsafe systems in place which means that braking systems come into operation to prevent two carriages being on the same section of track at any one time.

Reports also say the two men and two women who sustained serious leg injuries were still being treated on the scene by medics four-and-a-half hours after the crash, as some passengers were trapped 25ft in the air.

The four hurt, aged between 17 and 27, were airlifted to major trauma centres while twelve others on the ride also received medical treatment, including a man in his 20s who suffered neck and abdominal injuries.

Speaking with Sky News, Nick Varney, chief executive of Merlin Entertainments, which runs the park expressed his devastation at the event adding that the thoughts of the company was with the injured and their family.

He also added that the Staffordshire amusement park had "never had an accident like this".

Meanwhile, Merlin's share price lost more than 3% of its value on Tuesday as news of the accident reached investors.

According to the official website of The Smiler, the £18m ride is the world's first rollercoaster with 14 loops and opened in May 2013.

But the ride was affected by two incidents within the space of just six months, the first being in July 2013, when a metal bolt fell off the ride leaving a gap in the track.

After that in November 2013, passengers sitting in the front seats of the ride were hit when several of the rollercoaster's wheels fell off.