More than 5,000 competitors have braved bitingly cold conditions to attack an obstacle course billed as the world's "most dangerous taste of mental and physical pain".
Approximately 4,600 of those who took part in the 24th annual Tough Guy event at Perton, Staffordshire, completed the eight-mile challenge, while around 600 dropped out before the finish.
Event organiser Billy Wilson said he was not surprised that thousands of people continued to pay for the privilege of enduring Tough Guy's blend of mud, freezing lakes, barbed wire and fire.
"It costs about a million pounds to build a course like this and the event is different to anything else," Mr Wilson observed.
Asked how competitors had coped with temperatures hovering not far above freezing, Mr Wilson retorted: "The weather had been beautiful today - we must have a microclimate here because we've had bright sunshine.