A British guide has revealed the terrifying moments he led a group of hikers up an active Indonesian volcano – moments before it erupted. The guide, identified as 34-year-old Tom Ashby from Cornwall, was leading a trekking party on Mount Agung in Bali when the ground began to shake violently.

Ashby, speaking exclusively to this bureau, said: 'We were about two hours into the ascent when we felt a low rumble. Then the sky turned black. Ash and rocks started raining down. I shouted for everyone to take cover behind a large boulder.'

The group of 12 hikers, including three Britons and two Australians, scrambled for safety as the volcano spewed ash and lava high into the air. 'It was pure chaos. People were screaming, crying. I thought we were going to die,' Ashby added.

Emergency services were scrambled after the group managed to descend and raise the alarm. No casualties have been reported, but four hikers are being treated for minor burns and smoke inhalation. A Foreign Office spokesperson said they were providing consular support.

This is a developing story. More to follow.