Achmat Hassiem: 'I could feel my leg being torn apart... I was being attacked by a great white'

I caught something out of the corner of my eye, a black shadow in the water. I thought it was a seal or a dolphin and then this fin broke the water."

Achmat Hassiem and his younger brother, Tariq, gathered their swimming gear quickly, anxious not to disturb their parents' weekend lie-in. On a quiet Sunday morning it did not take long to clear their Cape Town suburb and reach Muizenberg beach, the long stretch of sand that sprawls east of the Cape Peninsula. They were excited; life-saving exams were looming and a busy day of rehearsal lay ahead. It was 13 August 2006 and their lives were about to change for ever.

Down on the beach they met the others, Nick, Kim and Kiesha, and squabbled good-naturedly over who would be the patients and who the savers; and then who would be dropped where in the water. "Nick didn't want to go any deeper than his knees. I jumped out and it was head height. My brother went deeper," says Hassiem, his memory five years later as clear as the Atlantic waters of False Bay. Muizenberg beach slopes gently into the bay and Hassiem had spent his childhood exploring, playing and swimming across its easy undulations. He knew it well. "I stood in the water and watched the boat go back to the shore. The whistle went and the exercise began. I watched them pick up Nick."

Shark sightings around the Cape are common; the sea there is a rich hunting ground but only at certain times of year and August is usually considered too cold – there is, after all, nothing between there and Antarctica. So when Hassiem first caught sight of the advancing shadow, his initial thought was not one of alarm. Then the tell-tale fin first pierced the surface.

Hassiem's voice is soft, his accent distinctively South African. "The shark was heading towards my brother. I screamed for the rubber duck [the life-saving boat] to get out to him. They didn't understand what I was shouting about – I was screaming, 'Get Tariq, get Tariq, he's in danger'. Then I started splashing, trying to distract the shark. The shadow changed direction. It was coming towards me and then the fin disappeared below the surface. I knew that when sharks attack they like to come from the bottom up. I could just touch the bottom and I tried to make myself as big as possible.

"But the shark didn't attack. It bumped me and its body rolled along mine, then its tailed whacked me. I was rocking, trying to keep my feet. I lost sight of the shark but I could see my brother further out. He was screaming something at me. Then I saw it coming. Its mouth was open.

"All I thought was to try and get away from its mouth, so I put my hand out and tried to push myself on top of it. My hand was on the shark's head and I tried to get my right leg over it. I couldn't move my leg and then I saw half of it was in the shark's mouth. It started violently shaking me; it was terrifying. I could feel my leg being torn apart but there was no pain. I was in absolute shock... I was being attacked by a great white.

"It shook me again and started trying to pull me under. The water was still quite shallow and sand was churning everywhere. The shark began to try and head towards deeper water and started picking up pace. I thought this was over, I was going to die. I remember the sound of the rubber duck's engine disappearing. I thought they had left me, but it was because I was getting dragged deeper. The ocean was becoming darker. I was still trying to get out of the shark's mouth. I was getting short of breath and I remember thinking why don't I just let myself drown – that would be better than what the shark would do to me.

"Then I decided, no, fight. I hit the shark with my fists. A shark's body is coarse and it was like hitting sandpaper, a tank wrapped in sandpaper. Soon I had no skin on my knuckles but I had one good leg left and I was trying to kick the shark. Then it shook me again, twice, and so hard that on the second one there was this cracking sound, even under the water – my leg broke off.

"I swam towards the surface and sound started coming back. I stuck my hand out of the water and that's when I saw my brother in the rubber duck. He grabbed me, saying 'Don't worry, I've got you'. I was hauled into the boat as the shark came back. It dwarfed the boat. It hit the underneath of the boat. My brother jumped on me to hold me. He closed my eyes so I couldn't see what had happened to my leg. Later he told me that there were perfectly cut triangles of flesh with bits of broken shin bones hanging out. But still I felt no pain."

They reached the beach and waited for the air ambulance to arrive. Tariq, at 17 the younger sibling by five years, kept his brother's eyes closed so he could not see the damage the shark had done. In the meantime somebody had reached their parents, the Sunday morning lie-in shattered. En route to the beach they were stopped by the police for speeding, although that was quickly transformed into an escort. It was as Hassiem was being loaded into the air ambulance that he first noticed his mother. She stood alongside his stretcher in tears. Lost in shock and awe – and still to feel any real pain – he gave her the thumbs-up.

Later that day, Hassiem was operated on, and up until the very moment the anaesthetic took hold, he still had no real idea what he had been through. He describes how there were moments when he felt as though he was looking down on himself playing a part in a movie. Reality arrived the following day.

He awoke in intensive care. "The first thing I saw was my brother crying. That hit me hard. He saw I was awake and said, 'Thank you'. I said, 'What for?' 'Saving my life,' he said.

"Then he said: 'You know what happened?' 'What do you mean?' 'Look under the blanket,' he said. I was scared to look. I looked and saw my leg was gone – that was the first moment I really knew what had happened. I'd always played sport, it was all I wanted to do. I went into this great depression.

"It was on my third day in hospital that the pain really kicked in. You feel like your leg is still there – I felt like I had cramps in my right foot, but of course I didn't have a right foot. It's the worst pain I ever went through. I was terrible. I remember waking one night, there was blood everywhere and I was yelling for the nurses. I couldn't handle it."

Sport had been his life before the attack and it was to be sport, and the prospect of still one day being able to wear his country's colours, that was to help bring him back to life. "One day Natalie du Toit came to visit. She suggested I got into paralympic swimming. I didn't really know anything about disabled sport – it's only once you are disabled that you realise how big it is and the opportunity it provides. I learnt about people like Natalie and Oscar Pistorius and thought – 'OK, there is still hope'."

Du Toit is an iconic figure in South African sport. She carried the country's flag in both the 2008 Olympics and Paralympics and has won able-bodied swimming medals at the Commonwealth Games. Pistorius too has succeeded on a global stage. They are the two best-known Paralympians in the world and have helped establish South Africa as one of the event's leading nations. They finished sixth in Beijing, ahead of Russia, Germany and France. Hassiem was part of that team, just two years after he lay in intensive care in Cape Town.

"The first time I got back in the water was really difficult," Hassiem recalls. "The first time I went underwater the fear kicked in. It took a couple of weeks to get brave enough to do it properly."

He specialised in butterfly and freestyle and is now in the world's top 10. A medal in London is his next aim, providing he comes through his national trials in March successfully. He has never been to this country before; he had never been outside South Africa before he flew to Beijing. This week he is in Canada, competing in the Pan-Pacific championships. He has also been to New York, an enthusiastic member of a group of shark-attack victims gathered from around the world by a charity to highlight the cause of shark conservation at a United Nations conference. "There we were, legs missing, arms missing, trying to defend the things that took them away from us in the first place," he says, his accompanying laugh displaying as much a trace of bemusement at the course his life has taken as the irony of the situation.

There was one place that he still had to go. "Getting back into the ocean," he says. "That was the worst thing ever. I wanted to do the Robben Island swim and so went down with some open-water swimmers to start training. They said they would look after me. It was not long before I saw a shadow in the water – it was a rock but it gave me such a fright. I sat on the shore and said, 'I can't do this'."

He was talked back into the water and cautiously began his training. Then came the morning of the race. "I woke up and I couldn't do it. The thought of swimming seven and a half kilometres through open sea... I kept thinking that with my leg I would look like an injured seal. I pulled out."

That was not the end of the story. He watched the race take place and decided that this was another battle he would not lose, and from someone like Hassiem, with his relentless, enriching enthusiasm, the ending comes as no surprise.

A year later he swam to Robben Island, with Tariq sitting in the boat that accompanied him, keeping an eye on the surrounding sea and urging his elder brother on.

"There are still nights where I sit down and thank God I survived the attack and have had all these experiences," sums up Hassiem. "People say sorry, but the rewards that have come are amazing. Losing a leg is nothing compared to losing a brother."

Follow Achmat Hassiem on Twitter – @achmathassiem