IN BRITISH WATERS AT LEAST, wrecks are the main motive for diving. Yet it wasn't always the case.
     In the early days of the sport, a strict class system obtained. Novices were only permitted below decks. Advanced divers were allowed into the passenger accommodation, but to gain access to a ballroom or Presidential Suite you had to be a First Class diver.
     New Labour put an end to all that, of course. In today's egalitarian society, all you need is anecdotal evidence of a 10-minute try-out dive in a Lanzarote swimming pool and you can dive the Lusitania on trimix.
     Another great advance has been the proliferation of "artificial reefs" - wrecks sunk deliberately to provide interesting environments for divers. The concept was pioneered at Stoney Cove, where the proprietors sank an airliner, a 60m bust of Elton John and the reactor unit of a decommissioned Magnox nuclear power station.
     The quarry was eventually drained to enable the Aga Khan to recover his favourite snorkel, but the concept of the "deliberate wreck" has survived. Recently, the frigate HMS Disreputable was hauled ashore at Rotherhithe to become the world's first all-weather dive.
     The idea has proved extremely popular among the 75% of British divers who never actually enter the water.
     In 1957, I participated in the most notorious "wreck dive" of all time. Entering the water just off Lulworth Cove, we landed upon the rusting conning tower of an ancient submarine. It was in a state of the greatest dilapidation, and we couldn't imagine why it hadn't previously shown up on sonar.
     It was only when the hatches of the missile silos sprang open that we realised it was a Russian nuclear sub on active duty. Assuming it was under attack, it had launched its full complement of warheads at London. Happily, immediately upon leaving the water, the missiles collided with a pair of paragliders in Ringstead Bay, and a devastating world conflict was averted.
     It was a wonderful example of collaboration between the adherents of two very different sports and, I think, reflected very well on each. A 400 square mile section of the English Channel was designated as an official war grave for the paragliders, so all's well that end's well.
     Among my favourite wrecks is that of the RMS Alopecia - a truly hair-erasing dive, you might say. In 1836 she was bound for Australia with a cargo of live sheep from Buckinghamshire. They were intended to broaden the genetic pool of the Antipodean Merino stock.
     Tragically, the Alopecia foundered off the Needles and, despite the valiant efforts of lifeboatmen, sank with all hands - and hooves.
     Yet to every cloud there is a silver lining - the incident inspired HG Wells to pen his masterpiece, The Sheep Of Tring Succumb.
     Wreck-diving isn't everyone's cup of tea. It can be an eerie and sombre experience, descending 50m in the cold and darkness to the looming hulk of a lost ship, its portholes black and enigmatic like the eyes of a corpse. Then again, some people think it's a real laugh.
     In the USA, Disney (the people who took the Grimm out of fairy tales) has responded by repackaging the wreck experience, replacing the sinister, frightening and morbid aspects with positive and upbeat imagery that every child will love.
     At UnderWalter World, The Little Mermaid guides divers around the glass and resin "wreck" of the ss Dumbo. They can take a break and sample the cargo of lollipops in Davy Jones' Licker Locker, or join Pooh and Eeyore at the Whale Meat Again seafood restaurant.
     See you in the queue.