Part of a hillside has collapsed in a disused slate quarry in north Wales where battle scenes from the hit fantasy series House of the Dragon were filmed.

A huge rockslide and a thick grey cloud of dust can be seen in video footage from a trail at Dinorwig Quarry in Gwynedd.

Aran Jones, 21, from Sling, Anglesey, was returning from a hike up Yr Wyddfa, also known as Snowdon, and trying to film goats when he heard “cracking” sounds and saw falling slate.

“Next thing as I’m filming the whole wall just collapses… I was mind blown… the last thing I expected to see,” he said.

“I kind of thought it might be a controlled demolition, but then I remembered the quarry’s been inactive since I think 1969.”

Opened in 1787 above Llyn Padarn, the quarry was at one point the second largest in the world.

It is part of the slate landscape of north west Wales, which is being developed as a tourism destination since becoming a Unesco World Heritage site in 2021.

The quarry was also a key filming location for House of the Dragon.

Gwenydd council said the site was privately owned.

Mr Jones was back in north Wales from his studies at Cardiff University.

“Luckily for me there’s a massive pit under the ridge [between Aran and the slide],” he said.

“I thought it was alright, but the minute I started to feel worried was when the couple I saw came sprinting down from the hill.

“Seeing the fear on their faces that like kicked in my flight or fright.”

Like the couple, he said he started to run as well.

“I was like, ‘God!, what if this is like a chain reaction? What if there’s more collapses all the way down the quarry?’

“So I just started running with them out of like sheer instinct.”

Mr Jones said there a number of off limits areas in the quarry, but he came across climbers who were heading to climb in the quarry that day.

He said he showed them the video and some said they were “looking forward to climbing the new routes that had been made from the collapse”.

It has had the opposite effect on Mr Jones.

“The main takeaway is just be careful.

“When I was there you could hear the slate dropping… cracking… the advice I would give is if you can hear any of that, just get as far away as possible.”