Theme park accident witness claims rollercoaster slipped off track - and heard 'horrific' screams

A theme park rollercoaster slipped off its track, an eyewitness claims, as he recalls hearing "horrific" screams.

Oakwood Theme Park in Pembrokeshire, south west Wales, was evacuated earlier this afternoon after a "serious" medical emergency.

The Welsh Ambulance Service was called to the scene at 1pm, with an air ambulance also arriving at the park.