Rutland runner was one of only two finishers within strict 55-hour time limit
Rutland Running and Triathlon Club member Bryan Clary has returned triumphant from an event which he described as the most horrendous to ever take part in.
Clary claimed first spot in the Tunnel Ultra Marathon after completing the gruelling 200-mile non-stop course in 50 hours and 58 minutes.
The event - believed to be the world's longest ever underground ultra-marathon - took place in Combe Down tunnel in Bath - an old railway tunnel which was closed for 50 years and reopened in 2013 as the UK's longest cycle tunnel at just over one mile.
It is one of several designed by Cockbain Events to push the physical and mental limits of the entrants.
Bryan, who was competing to raise money for Macmillan Cancer Support, was one of only two finishers within the strict time limit of 55 hours.
And he admitted afterwards that the competitors didn't know how hard the effect of the tunnel would be on them.
He explained: "The entrants were challenged with the tunnel being dimly lit for the majority of the day but then these lights were switched off between 11pm and 5am and it became pitch black.
"The rules also stated no headphones, walking poles and no outside support and I suspect we all underestimated the event.
"On paper it’s tarmac and flat but, after 100 miles, you notice every little incline and they feel like hills.
"We knew it would be boring, very boring - that was a given. But it was definitely the most horrendous event I have ever taken part in.
"The majority of people coped well with no sleep through the first night but it was the second night when the tunnel started to take its toll.
"The combination of being in constant low light when you are mentally and physically fatigued is very hard.
"Your muscles are seizing up after 24 hours in and, with extreme tiredness, it was a bit like watching an underground zombie apocalypse, complete with groaning."
One by one people dropped out through tiredness or injury, however, Bryan - who has done other gruesome events in this series such as running the entire length of Wales (250 miles in three days and three hours) - went through the worst of it before starting to hallucinate.
He added: "That would be OK for a few minutes but hours at a time with the walls appearing to move and becoming faces, animals, etc, and seeing clouds moving in the roof.
"The walls appeared to grow ivy and at one time I saw red poppy petals blowing down the tunnel in the wind towards me.
"I spoke to someone else and he had gone through a big cloud of flies so I wasn’t the only one wrestling with reality.
"I had no other option but to focus, look at the ground in front of me and push on.
"The last 10 miles were awful and I was grateful to Alan Cormack (the only other person left in the event) to have been able to run the last five miles with him."
This was Bryan's last ultra race in the UK so he wanted to raise money for a good cause as he and his partner Sue are leaving Rutland and emigrating to Canada.
He continued: "The Tunnel doesn’t sound like most people’s version of fun but that’s not the point.
"It’s the curiosity of what you as a person can really achieve, mental determination over physical exhaustion.
"Ultra running gives a perfect platform for people to explore boundaries and mental disciplines that are not possible in everyday life."