Tough Mudder Extreme Endurance Challenge 2012 - in pictures

Participants tackle the Mud Mile obstacle during the 2012 Tough Mudder Extreme Endurance Challenge held in the grounds of Drumlanrig Castle, Dumfriesshire Photograph: Andrew Milligan/PA

The 11-mile course is a test of endurance, stamina and fitness Photograph: Andrew Milligan/PA

A man falls backwards into the mud during the challenge Photograph: Andrew Milligan/PA

The Mud Mile is the eleventh of 22 gruelling obstacles on the course Photograph: Andrew Milligan/PA

Participants tackle the Firewalker obstacle Photograph: Andrew Milligan/PA

A participant tackles the Hold Your Wood obstacle Photograph: Andrew Milligan/PA

Participants pass through the Electric Eel obstacle, which conducts a shock of 10,000 volts Photograph: Andrew Milligan/PA

A participant tackles one of three obstacles called Kiss of Mud Photograph: Andrew Milligan/PA

Participants mount the the Walk the Plank obstacle Photograph: Andrew Milligan/PA

A participant covered in ice during the Arctic Enema obstacle Photograph: Andrew Milligan/PA

A tartan-clad woman feels the cold as she jumps into the Arctic Enema obstacle Photograph: Andrew Milligan/PA

Participants struggle through the mud Photograph: Andrew Milligan/PA

A participant tackles the Trench Warfare obstacle Photograph: Andrew Milligan/PA

Chris Steele looks for his trainers in a pile of abandoned shoes after the challenge Photograph: Andrew Milligan/PA