"EVERYONE PUSHES THEIR LIMITS. If you're an Open Water Diver, then a dive to 40m is a real challenge - but I've been there, and I need something more to push me to my limits."

Mark Ellyatt is unapologetic about his reputation as a deep, extreme diver. His last exploit, in which he beat Mark Andrews to the punch to set an unofficial 170m world wreck-diving record (Diver News, September), has already aroused admiration and condem-nation in equal measure.

His dives often take him into depths and conditions that would make even some of the most experienced divers quail. So what makes this Jersey-based Londoner tick - what has turned a former used car salesman into one of today's more infamous divers?

"I started in 1990, with a BSAC club, and did all the million length swims with a weightbelt, but I didn't really get into it until I went to Mexico and did my PADI Open Water course," he says. "It was the standard Mexican system - the dive boat forgot me, and left me in the water at the end of a dive! I was stranded between Cancun and Cozumel, puking and sunburnt, until they remembered me and came back - but it didn't put me off."

If anything, it seems to have encouraged him. From there, he embarked on a series of courses as the bug bit deep. "I was getting tired of the stuff I was doing - selling cars, a bit of ducking and diving, so I decided I'd try to make a living from the diving side of things"

A large amount of cash, and some cold experiences in Stoney Cove and other inland sites later, Ellyatt was a qualified instructor by 1994. From there it was on to full-time work in Barbados. It sounds idyllic, but it wasn't without its problems.

"This one guy came over, and asked to do some deepwater stuff - 60m or so on air, one to one. So down we went, over a ledge and down a wall. Right down there, all of a sudden I looked round and he'd taken his jacket off, dropped his regulator and was swimming away from me!

"I chased him and tried to get him to take my octopus, but he wasn't having any of it. He wouldn't even take my own reg. In the end I had to grab him hard and swim him up, nearly to the surface, before he took some air. I got him out of the water and asked him what the **** he was doing. Turned out he'd just discovered he was HIV positive, and wanted to top himself!

"I was very angry about that - he could have killed me too. If he'd wanted to do it on his own, he could have done so - I'm not Mr Compassion."

1994 saw Ellyatt taking things further, qualifying in nitrox and moving towards trimix and deep dives. This led to a passion for pushing his limits, and a reputation for achieving ever more challenging dives. The recent wreck dive in Hurd Deep followed a 180m plunge there last year. He maintains that the experience from these extreme dives helps in his regular instruction.

"I'm a full-time instructor, in hard-condition UK waters," he says. "I feel I should be that much better than the next person. I need to know that I can cope in the most difficult circumstances. And I need the challenge - when I want to let my hair down, I try to push my limits that much further."

It's not as though he hasn't got the training or experience for it. He has more badges than a busy boy scout, as a PADI Master Instructor, Medic First Aid with a dozen or so specialities, TDI Advanced Nitrox Instructor Trainer, Extended Range Instructor Trainer, Trimix Instructor, Rebreather Instructor, Gas-Blending Instructor Trainer, caving up to Full Cave Diver, numerous repair clinics, boat captain's licence, Powerboat Instructor for the RYA...

Ellyatt sells watersports equipment for Surf Dive and Ski on Jersey, and has use of its waterside bunker, which was built by the Germans during the Channel Islands occupation, from which to carry out diving instruction under his own name.

And he holds strong views about the instructor system. "I think too many people are learning to dive," he says, not something you hear every day from trainers. "It's not a sport for everybody, but they're trying to make it a sport for everybody - not just PADI, but all the diving organisations. I will fail people who don't make the grade and won't be happy or safe in the water.

"I believe that should be carried through to instructors too - there are far too many shabby instructors out there.

"I think all instructors should be at least extended range or trimix-trained, even if they're not interested in those styles of diving. They should be able to talk about it because they're diving instructors - they should be able to talk about all facets of diving."

And he could begin to create that master race of instructors soon, as his next ambition is to become a course director and further the sport from the grass roots.

Of course, his hard-core exploits are not without a high amount of risk. Ellyatt has been bent three times, the last time after the 180m Alderney dive, when his suit leaked and, he says, gave him hypothermia. While grateful for the attention he received, he has not always been impressed with the way some doctors handle DCI cases.
"I'm pretty disappointed in diving doctors - they encourage you to report any bends, but when you do, they say you're irresponsible and give you a hard time - whereas if someone breaks an arm skiing, they're told: 'Bad luck, don't do it again.'

"In my experience diving doctors have very little experience in things they should know a lot about - treatment that I've received has actually aggravated a bend, when they left a blood-pressure cuff on my arm! I don't want to slag off all diving doctors, but a lot of them seem to have egos higher than their qualifications."

Ellyatt himself can come across as almost arrogantly confident in his ability to handle a crisis - "I have a very high panic threshold - I don't panic" - and believes he has a natural ability to dive in serious conditions. "I've been given a body which doesn't seem to mind too much," he says.

And he's happy to be seen as someone pushing the sport forward and encouraging people to take it further. "No one would want to go to a Dive Show to hear someone talk about how great their first open-water dive was. If they can hear someone like me, though, talking about what it's like at the extreme end of things, then they'll realise there are a million more things they can learn."

That said, he is unhappy about accusations that he is encouraging people to take risks that are beyond them. He says new divers should be prepared to work at their skills, and build them gradually before attempting anything too serious.

"I don't think people should try to do the things I do unless they've done the things I've done. They shouldn't think that because I can do it they can. You need to build up the learning and experience from 10 years of diving like I have before trying the really big dives."

With views as extreme as some of his wilder dives, Ellyatt will always be a figure of controversy. The conservative lobby has accused him of foolhardiness, and bringing the sport into disrepute. "Rivals", such as Mark Andrews, who he beat to the wreck of the Baden this summer, claim he dives with inadequate safety measures and a disregard for other people's safety.

There is no compromise with Mark Ellyatt. No maybes, no hesitation, no debate about the rights or wrongs of what he does or how he does it. Yet friends and buddies such as his regular support divers Mat Thomassen and Pete Daw say they have complete confidence in the ability he has gained by pushing the edge that little bit further each time.

"What are you up to this weekend?" I ask Ellyatt, anticipating some adventurous scheme. I am not disappointed. "Well, tomorrow I'm off to a site just north of Alderney - I've got some co-ordinates for an undived wreck which is in about 120m - rumour has it that it's an aircraft carrier or something, so I'll drop down and have a look.

"Then, on Saturday, I'm going to look at the Affray, a sub that's in about 90m. Oh, and I've got some Open Water Divers to train, too..."