A PROBE is under way to determine how a passenger bus burst into flames on Sunday evening.

The Borders Busses vehicle was parked in a lay-by off the A7 near Heriot after suffering a fault just after 7pm.

It is understood the driver reported a smell of burning and requested a replacement vehicle to complete the service journey.

The parked up vehicle was discovered less than an hour later with flames coming from the front end.

A Borders Buses spokesperson said: “We can confirm there was a fire on-board a Borders Buses’ vehicle.

“No-one on was on the vehicle at the time of the fire.

"The vehicle was stationary and out of service.

“An investigation is currently underway to establish the cause of the fire. All other authorities have been notified."

Fire crews from Dalkeith and Musselburgh were rushed to the scene at 8.06pm.

Despite their best efforts the vehicle was almost completely destroyed by the blaze.