THE cause of a blaze which burnt out a bus at the side of the M4 motorway on Monday night is still under investigation.

All 16 passengers on the Stagecoach bus, on route X3 from Abergavenny to Cardiff, got away safely thanks to the quick-thinking and professionalism of the driver, said a spokesman for the company.

He said: “The bus has been recovered and we are currently investigating the incident.

“Safety is our priority and we are pleased to report that the driver acted in an extremely professional manner as he got everyone well away from the bus to safety.”

South Wales Fire and Rescue Service said the cause of the fire, which happened at 5.40pm on Monday night eastbound between Junction 30 and Junction 29, was accidental.

Crews from Maindee, Duffryn and Roath tackled the fire on the hard shoulder and two lanes of the motorway were closed for safety. The fire was extinguished by 6.20pm.