Stephen Thomas was surfing with his mate, Anthony, near Ceduna on the Great Australian Bight, when a White Pointer shark attacked.
The pair were about 400 metres offshore when Steve saw his friend being dragged through the water. With great bravery, he leapt on to the shark's back, hitting and punching it and pulling back its snout until it released its victim.
'Afterwards I was really surprised. I was on autopilot,' he says. 'I was yelling and splashing and swearing at the shark, but if you asked me today, would I do that again, I'd just laugh and say: never!'
The two friends, one seriously wounded and bleeding heavily, made their way slowly to the beach, while the shark attacked again and again. Eventually Steve managed to jam the side of his surfboard into its mouth.
On shore again, he was able to administer first aid to Anthony, then drive him to Ceduna where he was transferred to an ambulance and taken to hospital.
Steve says despite the experience he's still a keen surfer and occasional volunteer lifesaver, and he bears sharks no ill will.
'You can't predict where or when a shark attack might happen,' he says. 'But attacks are extremely rare despite the publicity they get. We have to avoid developing a vigilante mentality about sharks.'
Steve Thomas was awarded the Star of Courage in 2002, an award given for acts of conspicuous courage in circumstances of great peril.