You can’t mistake the flags: big, white, with a large black shark on them. And the flags were up. British-born accountant, 42-year-old Michael Cohen approached the beach. Lifeguards and shark-spotters told him the situation. But this was far from the first time for this kind of conversation. Mr Cohen was in the habit of ignoring the warnings.

Yesterday at Clovelly Corner, near Fish Hoek Beach close to Cape Town, it was no different.

30 shark 6201 Surviving a shark attack: a seal, two belts, a wetsuit and spiritual guidance

As Cohen approached the water – no wetsuit, just swimming trunks – shark-spotter Monwabsi Sikweyiya approached. He said sirens had been sounded earlier because several sharks were present – thought to be great whites – in the bay.

Skiweyiya said: “He told me he had respect for sharks and if he was taken by one he said – tell people it’s my fault, not the shark’s.”

There was no stopping him and he went in. Several more warnings were shouted. But this was how it was with Michael Cohen. On previous occasions he’d even suggested he leave his car-keys with beach-guards “in case something happens”. His Facebook site lists sea-swimming as his favourite hobby. And sea-swimming with great white sharks is, no doubt, a break from his day job – accountancy.

They shouted more warnings as he was in the water. It was now a little after 10.45am. Several sharks were in the vicinity. At least two were now so close in to shore that people could – and did – video them as they patrolled the clear, cold waters of the bay.

By now Cohen was the only person in the water. All surfers and bathers long since out since the renewed sirens and white flags were hoisted along the bay.

Michael Cohen didn’t know it, but as he was arguing with the shark-spotters on the beach, two men were driving home along the coast from their shift at nearby Pollsmoor Prison.

‘It’s my life, it’s my choice’

On the beach the argument was continuing. Shark-spotter Sikweyiya said: “I said ‘dude, you have no idea how other people can be affected by this, starting with your family, beachfront people, shark spotters, a lot of people can be affected.’”

Cohen looked at him and said: “It’s my life. It’s my choice.”

And he entered the water alone.

At that point, coming home from their prison shift where they are spiritual guidance counsellors, were Douglas Drysdale, 61, and Hugh Till, 66. Neither young men. But experienced men. They know the place. They know the beach. They took one look at one man in the water with dark shapes moving around and were onto emergency services at once. They knew this was not if, but when. They raced to the beach by which time the tell-tell patch of bright red sea water was already plain around Michael Cohen. And people were already screaming for help.

Rescue

Both entered the water and began dragging Cohen to the shore. It was not easy against the current and surf.

By now the screaming from the beach was frantic. People were seeing either the same or another great white coming in, sensing the blood, apparently for another strike.

And then, as they struggled to get Michael Cohen out, another shape appeared in the water, smaller and more blunt in shape: a seal. To the astonishment of onlookers, the seal began circling the three men as they attempted the rescue, moving to ever more shallow water. In doing so it appeared to divert the incoming shark’s attentions as they finally got Michael Cohen clear of the sea.

Mr Cohen’s extraordinary run of luck though, had only just begun. Instantly shark- spotters began cutting up the arm of a wetsuit and, using a couple of belts, applied them as a tourniquet to his right thigh. His right leg had been bitten off completely below the knee and was gone. His left, a mangled mess of broken bones and ripped up muscle and tissue around the left ankle area. Part of his left calf was bitten off. Michael Cohen was bleeding out rapidly and would soon have been dead but for that crude but vital tourniquet.

Later in hospital, Professor Andrew Nichol, a trauma surgeon, said Mr Cohen is “very, very, very lucky to be alive” and paid tribute to those bystanders whose tourniquet had, he said, saved the man’s life.

Four surgeons fought to save his left leg and it is believed they have succeeded – though Michael Cohen is, and will remain for some time to come, critically ill and will require further surgery in the coming days and weeks.

Mr Cohen remained fully conscious on arrival at hospital by helicopter although he was “disorientated and confused” but even by the time he was being stretchered into the helicopter on the beach, IV lines were in both his arms, oxygen was being given and his very weak pulse was returning in strength. On the operating table he would need more than seven litres of blood.

As well as all the immediate medical issues he faces, there is the question of infection. Are shark-bites infectious as well as potentially lethal, if you survive the original attack?

And on this, it seems, very little is known.

The final word best left to Professor Nichol . Asked about infection at a press conference, he said, with commendable understatement: “We know very little about this. In fact, it is rather difficult to do a swab on a great white shark.”

Follow Alex Thomson on Twitter: @alextomo