I WAS BITTEN BY THE DIVING BUG during a round-the-world promotional tour for my book The Devils Alternative, so it must have been 1978. I remember that Id left Western Australia feeling utterly exhausted. Id done Toronto, Vancouver, Hong Kong, Brisbane, Sydney, Melbourne and Perth, and I had a three-day break before going on to Johannesburg.
Somebody suggested that I should drop into Mauritius for a rest, so I happened to be sitting by the pool at the St Gerain when the activities director came by, asking if anyone was interested in doing a resort course.
I thought I might as well give it a go, so off we went. He kitted us up, took us outside the fringing reef, got us into the water, and that was it. I was hooked.
For the next seven years I kept doing resort courses, then finally decided to do it properly, so I got a PADI instructor to come up to the farm in Hertfordshire.
We did the poolwork in our own swimming pool and the bookwork on the dining-room table. My sons Stuart and Shane, who were only 10 and 12 at the time, did the course with me, and we got a referral to the British Virgin Islands to finish the qualification.
Weve dived all over the place on family holidays, but my logbook is a mess so I have no idea how many dives Ive done - we went to Grenada and the Grenadines and Ive got nothing to show for it. Ive dived in Kenya, Grand Cayman; the Gulf of Oman and the Turks & Caicos Islands. We went to the Maldives, but I thought it was a bit disappointing after El Niño.
We once chartered a boat in the Seychelles and dived around the Amirante Islands and Desroches, which was wonderful. There were no other divers and it was pristine apart from the bleaching. The only unfortunate aspect of the trip was not being able to reach Aldabra. Its the biggest atoll in the world, 700 miles off the Seychelles, and the diving is supposed to be fabulous.

Dressed like Darth
We went to Tobago, but I wasnt that impressed; the boats were very basic. When you have six grown men dressed like Darth Vader, all teetering around in a small space trying to get organised, its not a good situation.
I didnt enjoy Honolulu much either - theres very little good coral, bad visibility, a terrific surge and booming breakers. Its more of a surfers paradise.
In November 2003 I was diving off Cabo San Lucas on the tip of Mexico, and we were in Antigua for Christmas and New Year. Earlier in the year, we chartered a liveaboard on the Belize barrier reef.
That was the famous occasion when I opted out of a dive one day to read and relax - just one dive - and my sons came back full of excitement because theyd seen a whale shark. I couldnt believe Id missed it.
For me, diving is about pure relaxation. Its weightless and silent, and where else can you find that in the modern world I love coming back from a dive, flopping on the sunbed and thinking: Now that was great.
I enjoy letting my mind drift off to all the fantastic things Ive just seen: corals, gorgonians, big schools of barracuda, tuna, jacks, snappers, sharks. Its a world away from work.
When I get an idea for a book, I spend a year working it out, then six months researching - travelling, storing, filing and collating. I end up with a suitcase full of articles, maps, interviews and tearsheets, and a clear idea of how the story is going to unfold. Then I sit down and type it all up.
I always use a typewriter. I tried using a computer once, but I spent far too much time going back over what Id written, and just couldnt get used to working with it. I kept wanting to Tippex things off the screen! I get thoroughly involved in what Im doing, and diving is my escape.
  Once Ive finished a book, I pass it to my agent and, while the publishers are reading it, I always take myself off somewhere to hover over a reef. Thats all I ever want to do.

Stealth bombers
One of the best places I have dived was Lizard Island on the Australian Barrier Reef, where you find huge potato cod and clams a metre long, but one of my most memorable moments came when I was diving further down the coast off Thatcher Reef, part of Flinders Reef.
It was very odd. I was on a three-day liveaboard trip, but for some reason all the other guests were geriatrics who just wanted to snorkel, so I ended up diving on my own with the divemaster.
One day we came across five manta rays. They appeared silently through the gloom, gliding towards us in formation.
As they approached, it was like being hunted by a team of stealth bombers; then they just floated past, completely ignoring us.
I remember that one of them was covered in cleaner wrasse - there must have been 20 of them hanging off it, washing it. I had only ever seen one manta before, in the Gulf of Oman, so it was a real treat.
Another great moment was seeing 10,000 schooling barracuda in hunting mode off Phuket.
They must have been flying through the water at fifty knots, 2m long, well marked, with mouths wide open. Id never seen anything like it.
We had to cower into a crevice and crouch under an overhang to get out of their way. Thats the kind of thing that really gives me a buzz.
Im not greatly interested in wrecks. Examining US bombers and Japanese flat-tops doesnt hold a fascination for me, although I did dive the wreck of the Rhone in the British Virgin Islands and saw a 300kg jewfish - huge, but very shy and harmless.
Im not a fan of coldwater diving, either, so Im not tempted by the English Channel or Scapa Flow. I will only dive in reasonable water and with good visibility. I like to be able to wear a shortie, so I can have my hands and feet free; I dont like the sensation of being in a straitjacket.
I havent been to the Red Sea yet, so thats probably next on my list - Port Sudan, the Gulf of Aqaba, Sharm and Ras Mohammed. The Sudan can be very fundamentalist but you find amazing coral, hardly touched.
Im not a particularly adventurous diver these days. Its not fear, its lack of physical fitness. I draw the line at doing anything too strenuous.
Im not fit enough for tekkie diving, and I wont go beyond 30m because of the safety stops. Im not keen on shore-diving either. If I have to walk to the water with all my kit on, Im exhausted before I even get my head down.
I like to dive off a deck or RIB, but even then I need the help of a muscular young man to grab my BC and give me a good yank. Thats what comes of having too much lower body weight and not enough upper body strength. Its a shame, really, because theres a great place around the Cocos Islands, 300 miles off the west coast of Costa Rica, where you find hundreds of schooling hammerheads, as well as great whites and tiger sharks. You have to motor for 30 hours through bucking seas and riptides to get there.
Then you get into the water and, imagine: as youre battling with the current, you look behind you and see a lot of seriously frightening things coming towards you. It sounds fantastic, but I wouldnt do it. Its tempting fate. Of course, if I was 30, it would be a different story.

Like a torpedo
I have a passion for all things squalis - nurse sharks, basking sharks or leopard sharks, with their tiny blind eyes. When you look at a shark you can see that its been unchanged for millions of years.
I find it absolutely intriguing but, unfortunately, it inspires universal abhorrence, no matter what it does.
Its the half-grin, and the way it moves like a torpedo, or like a jet fighter cutting through the water. Its a dangerous piece of meat, but you have to admire its sheer dynamic perfection. You look at it and think: it was perfect when it was created, and its perfect now.
I strongly disagree with the panic induction that goes on - Peter Benchley himself has said that his film Jaws costs 100 million sharks their lives, yet only 12 people a year die from shark attacks. After the film was released, the USA started a killing spree, and the truth is that 99% of sharks would never touch anyone as long as they are left alone.
The situation is now so serious that it has become an eco-hazard, and a film like Open Water is not going to help matters. If were not careful were in danger of exterminating the shark completely.
Having said that, Ive always been keen on deep-sea game fishing, and see no conflict between fishing and diving from a conservation point of view. Admittedly, it used to be the done thing to catch sharks and bring them on board to die.
I even wrote a short story called The Emperor, part of an anthology of short stories called No Comebacks, which was based on a trip with the St Gerain boat in 1978 when we caught an oceanic whitetip. But I dont kill any more, except for the pot.

Ive become more aware of the conservation issue over time. About 15 years ago I realised that it was madness to kill, that fish were not an infinite resource. When you watch a series like Blue Planet and see trillions of schooling sardines, you think they must be limitless. Then you see an orca going after them and realise that there cant be that many.
Mind you, one man with a rod and line isnt going to do any damage. Ive been to a great marlin-hunting spot off Madeira where huge marlin gather between May and October, without fail, every year.
Nothing is ever taken from the ocean - whatevers hooked is thrown back, and the fish never quit the area.
Theres not much wrong with fishing itself. Its the long-liners and trawlers hoovering the seas with their ultra-modern fishfinders and small meshes that are the problem.
Unfortunately, you have to go further and further afield these days to find privacy and unmolested sea life, but there are still some remarkable places - the Marshall Islands, Truk Lagoon, Guadalcanal, the Solomon and Andaman Islands.
I was supposed to dive in Fiji not long ago, stopping off after a city-a-day promotional tour for my latest book, Avenger, but by the end of the tour I just wanted to come home. These days I find I want to be away from home for shorter and shorter periods.
I havent done any of Micronesia, Melanesia or Polynesia. Id like to explore those areas, but they are a brute to get at, and the boys are now in their 20s, so they find it hard to get time off work to come diving.
And my wife, Sandy, is not a diver. Shes not very aquatic. She puts up with me diving in return for a shopping trip to Milan - which, I suppose, is fair enough!