LEADING ARTICLE: Greenpeace, right or wrong

How on earth can we expect citizens to be good recyclers, to waste and pollute less, if the British government allows an extremely wealthy oil multinational to toss a dirty, redundant old rig into the Atlantic?

That was the question angry European environment ministers put to their UK counterpart, John Gummer, at last week's North Sea conference. Greenpeace added others. What has happened to the "polluter pays" principle? And what precedent does Shell's imminent dumping of the Brent Spar set for the disposal of more than 200 other offshore oil and gas structures in UK waters?

These are all relevant questions and it is right that they are put. But in the end, we must also address the specifics: ''What is the best way to deal with the Brent Spar now?'' Hard though it may be to accept, the answer, on balance, is to tow the edifice out into the north-east Atlantic and then allow it to plunge 6,000ft to the sea bed.

Down there the Spar, not a rig at all but a gigantic oil storage tank, will poise no serious environmental danger - not to fisheries, the wider ocean, or to any people. The list of hazardous contents sounds scary; 100 tons of oily, silty sludge, toxic heavy metals such as cadmium, arsenic and mercury, even some radioactivity. But the quantities involved (about one pound of mercury, nine tons of oil, radioactivity equivalent to that found in several granite buildings in Aberdeen) mean that the only risk is to deep-sea creatures within a few hundred yards of the sunken structure.

Opponents argue that the structure poses a wider environmental threat - their objections are based on principle. Shell, they say, should dispose of the Spar properly on land, recycling the bulk of it and putting any hazardous portions in safe disposal sites. Shell replies that this course would cost an extra pounds 35m. The exact sum can be questioned, but bringing such a vast structure back on land and breaking it up would certainly cost very much more than sea dumping.

Making companies, even very large, wealthy ones, spend millions on unnecessary, symbolic clean-up operations is a bad idea. In this case taxpayers would also lose out since Shell can claim considerable tax relief on decommissioning costs.

Besides, there are threats to the environment and human safety in breaking up the Spar and bringing it ashore which sea dumping avoids. Land disposal would require more energy to be consumed by tugs, lifting gear and other heavy equipment, with extra air pollution as a result. The accommodation decks contain asbestos, not an underwater hazard but damaging to humans if released during demolition work on land.

Yet the fate of the Brent Spar must not be allowed to set any kind of automatic precedent. When other North Sea oil installations become redundant, owners must establish afresh the best disposal option in terms of cost, human safety and the environment. That requires public discussion, transparency about the numbers and an appropriate period for consideration. Greenpeace has performed a public service in drawing public attention to the issue of North Sea dumping. It should now declare victory and move on.