A mountain bike athlete rode a nail-biting trail that lead down the narrow tunnels of an abandoned lead mine.

Cyclist Jono Jones, 29, took 30 minutes to finish the 10-kilometer trail - hurtling down the tunnels at 40 kilometre per hour.

Jono, from Milton Keynes, Buckinghamshire, was

nervous as the trail is underground and isolated meaning medical attention would be four to five hours away.

He and his guide relied on lights to avoid crashes and painted arrows to avoid wrong turns leading them deeper into the mine.

Jono, a professional mountain biker, was invited to ride the trail as part of a mystery tour organised by Goodyear Tyres and the Slovenian Tourism Board.

The tour's destination was revealed to Jono at the airport where he was told he would be flying to Slovenia and head to the mountains near Jamnica.

Jono said: "I've ridden my whole life competitively but I've never seen anything like this. It's so weird and underground. "

"The whole time I was nervous about hitting my head on the roof. You have to duck as you go. "

"The tunnel is also really narrow. You have to keep your handlebars from hitting the sides and the shadows from the lights make massive blind spots."

"The whole time I was thinking 'If these lights go out I would definitely get lost in here'."

"We were kilometres underground so I was nervous of getting hurt - help would be hours away. "

"It would be a disaster to have to get someone out."