Much of the interest, though, comes from medical researchers who hope the strange properties of some of these creatures may lead to new anti-carcinogens or tumour-reducing drugs. Some more familiar forms of life, found in much shallower waters, also hold out the promise of new medicines. Sea cucumbers, for instance, are already being harvested and minced up by French and American pharmaceutical companies. Chemicals isolated from soft coral off Western Australia may help fight breast and ovarian cancers.

Old hands cast doubt on theories that huge quantities of minerals lie below the seabed. Big seams are needed if money is to be made. But most of the compounds found so far, say the doubters, come from volcanic deposits. Dissolved minerals — copper, gold, silver and so on — typically rise up with volcanic activity and then become sea-floor deposits; the surface copper in Cyprus, a volcanic island that was once below the waves, is an example. William Ryan, of Columbia University’s Lamont-Doherty Earth Observatory outside New York, says there are fewer nodules than people generally believe and most of them are in very deep water. He adds that everything done at sea is becoming more expensive, so the economics of mining may not have improved much. He is equally sceptical about methane hydrates, arguing that the energy they contain is less than the energy needed to release and secure it.

Such cautions may be wise, but they will not stop the scramble. Too many mysteries of the deep remain unexplained and, anyway, no country turns down a chance to enlarge its sovereignty.

... contd.