I’ve always wanted to learn to dive, for as many years as I can remember. But thanks to Jaws, any chance of getting me in water much deeper than waist level was pretty much dashed.

The problem, as I saw it, is that I’m a 6ft (1.8m), 15-stone (92kg), overly macho male — who is afraid of fish. If it’s not battered and served with chips, I don’t want to know about it. At least that was my thinking before doing a British Sub Aqua Club (BSAC) ocean diver training course in the tropical waters of the Cayman Islands.

So here I was getting ready to start a four-day course beginning in the safe shallows of a pool and ending in the ocean at a place called Stingray City. It’s never too late to challenge your fears.

Fortunately, I wasn’t alone. Three others were there to throw themselves into the deep. Sharon, Amy and Kelly were like me — absolute beginners, but eager to learn.

The training started early. Our instructor, Sebastian Chander, met us at the dive shop at 7.30am. After being issued with wet suit, mask, snorkel, fins, and breathing regulator, we were in the pool getting used to swimming in the wet suit and using the snorkel. We progressed quickly and in no time were using an aqualung to breathe under water.

When I first went under I didn’t trust the equipment. Hadn’t we undergone millions of years of evolution to get out of the water? It didn’t take long, though, to get over the jitters, and soon all four of us were swimming back and forth as if we were lifelong divers.

Sebastian ran us through a series of training exercises. We learnt what to do when we ran out of air, how to help an injured dive buddy, and how to clear a mask — blowing hard through your nose to force air out. Seb told us that by the following afternoon we would be ready for our first ocean dive.

Next morning, the sky was a cloudless blue. We stood on a jetty, baking inside our wet suits, as Seb laid out the plan for our ocean dive. After getting into the water we were to swim to a buoy about 150ft out. From there we would descend in pairs to a sandy patch 12ft below the surface.

Once submerged, Seb would run us through more exercises.

That all sounded fine to me, until I actually got in the water. It’s amazing what images your mind can conjure up while swimming in tropical waters. Nothing vicious ever seems to happen in the cold waters of the northern hemisphere; the nasties always seem to favour equatorial warm waters. Can’t say I blame them.

After getting over the fear — mostly — the whole undersea world was different. Even Sebastian had transformed. He went from being simply a dive instructor into Scuba Seb, Man-Fish. He looked as at home in the deep as I do on a barstool. Still, we were beginners and I was confident our abilities would improve.

Our training continued for two days. There was more mask clearing, more buddy breathing, and more exploration of the reef and its inhabitants. The more sure I became of my equipment and skills, the less I dreaded a sneak attack by Spielberg’s big white shark.

Exiting the warm waters on that last training dive, all that remained was to find out if we had passed the course. It was a tense couple of hours waiting by the pool — beer in hand. One by one Seb called us into his office, and one by one we got the good news. We all passed and officially became BSAC ocean divers. The deep will never be the same again.

Need to know

Doug McKinlay travelled with the BSAC (0151-350 6200, www.bsac.com) and BA (0870 8509850, www. ba.com), which flies from Heathrow to Grand Cayman from £697.80. Cobalt Coast Resort and Suites (001 345 946 5656, www.cobalt coast.com) has one-week dive breaks from £710pp.

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