The Smiler rollercoaster in Alton Towers has been evacuated due to a safety concern.

According to a spokesperson for the park, the ride was stopped following a problem with a safety harness.

The Smiler was closed for 30 minutes so engineers could reboot the computer system responsible for monitoring the safety sensors.

"At 10.15am, an assisted exit took place in the station when a guest, at the end of their ride, held their harness down during the routine harness release, triggering our sensors," the spokesperson said.

"The ride then needed to be reset as required by our operating processes and is now re-open."

This comes after an awful accident in 2015 where two teenage girls lost a leg each and 14 others were injured after safety failings.