The wildlife is ­thousands of years old, there are species upon species that have not yet been discovered and it is key to the survival of the planet.

But environmentalists say our rich undersea habitat is now being destroyed.

The deep ocean environment is perhaps the most important and least understood of the planet's natural habitats. But in the west of Scotland it has been targeted by foreign fishing trawlers that drag heavy nets across the seabed, damaging everything in their path.

The European Commission (EC) has proposed a ban, unleashing fury from the fishing industry and meeting opposition from the Scottish and UK Governments. But pressure is now mounting on ministers to back the ban, with a petition signed by nearly 15,000 people and promoted by a coalition of 10 environmental groups.

Allowing the trawling of the deep-sea bottom is like letting "Stonehenge be bulldozed", they say. But this is angrily disputed by fishing leaders, who attack environmentalists as "emotive" and the EC's proposed ban as a "knee-jerk reaction".

The deep sea, defined as waters deeper than 200 metres, makes up 98% of all the space in which life on earth can develop. It is the world's richest source of wildlife, with an estimated one to 10 million species still to be discovered.

Off Scotland's shores, however can also provide rich pickings for fishing boats. French and Spanish trawlers report annual catches of around 6000 tonnes each. Much of this is from UK and Irish waters, including the ­northern Atlantic around Rockall to the west of Scotland.

Deep-sea trawling has been described by some scientists as "the most destructive kind of fishing in history". Environmental groups point to more than 100 scientific studies suggesting that it is unsustainable and harmful to underwater wildlife. They have also recruited more than 300 international ­scientists in support of a ban.

If Scots realised that foreign ­fishing boats were wrecking the nation's natural heritage they would be outraged, argued Claire Nouvian, director of the Bloom Association in Paris, which works to protect the deep ocean from trawling. She has been co-ordinating the campaign for a ban.

"If the Government supported a law that allowed Scottish castles and outstanding natural features to be wiped off the map to develop intensive, monoculture farming, Scots would probably march on London to stop it," she said. "The same is going on in Scottish deep waters but just because that part of Scotland's beauty is hidden under water, very few even know."

The UK Government's Fisheries Minister, George Eustice, has recently admitted that only 12 UK fishing boats trawl the deep-sea bottom below 600 metres. Nouvian contented that a ban would not lead to a single job loss in Scotland.She accused the fishing industry of "playing dirty" by trying to discredit environmental groups. "Deep-sea fisheries are a mistake of the past," she declared. "The Scottish and UK Governments will not be forgiven if they fail to seize this historic chance to preserve the UK's exceptional marine environment from the destruction imposed mainly by French and Spanish vessels."

She was backed by the National Trust for Scotland, which argued that it was impossible for deep-sea fisheries to be sustainable. "Most deep-water species are incredibly long-lived," said the trust's senior nature conservation adviser, Dr Richard Luxmoore. "Anyone who claims to be managing these fisheries sustainably is trying to pull the wool over your eyes."

Pete Ritchie, director of the sustainable food campaign, ­Nourish Scotland, described deep-sea fishing as "environmental vandalism". He said: "Out on the deep sea bed towards Rockall we are allowing industrial fishing boats, mostly from France and Spain, to create an underwater desert which is at least the size of Fife."

Professor Murray Roberts, a marine biologist who co-ordinates Heriot-Watt University's Lyell Centre for Earth and Marine Science and Technology, pointed out that many of the deep sea's natural treasures may not yet have been found. "We know that bottom trawling destroys vulnerable marine ecosystems like deep-sea corals and sponge grounds," he said. "Nations are duty-bound to minimise this damage."

The fishing industry, however, insisted that it supported more sustainable deep-sea fisheries management and was working to protect coral and vulnerable environments to the west of Scotland. A blanket ban would be "completely disproportionate", according to Mike Park, chief executive of the Scottish White Fish Producers' Association in Fraserburgh.

He accused environmental groups of ignoring the science and thrusting the issue on the EC and the European Council of Ministers in pursuit of a "social ideology". A ban would have "serious socio-economic consequences for not just the Scottish but for the entire European Union fleet", he said.

"The long-term sustainable management of fish stocks requires intelligent regulation and not emotive, ill-thought-out, sweeping policies which have the potential to eradicate a sector and set a dangerous precedent."

Park pointed to scientific evidence that vulnerable ecosystems were being protected by European regulations and the proposed network of marine protected areas around Scotland. "These areas are protected because they correspond to pristine or very low-impacted ecosystems," he said. "Marine Stonehenge has not been bulldozed."

Although he said it was not ­possible to verify how many fishing vessels were involved in deep-sea trawling, Park was certain that the proposed ban would cause UK boats problems. "There may only be 12 UK vessels involved. However, these are larger vessels making a significant contribution to coastal economies," he said.

The Scottish Government took a similar line, rejecting "an ill-thought-out blanket ban on bottom trawling". It supported protective measures in areas where fishing vessels actually operate, and strict management controls outwith those areas.

"This targeted approach provides more precise protection for sensitive habitats as being more readily enforceable," said a Government spokeswoman.

"The Scottish Government is firmly committed to protecting vulnerable marine ecosystems and we are keen to see the adoption of deep-sea regulations that are both effective and proportionate."

The EC proposal for a ban on trawling the deep-sea bottom is due to be decided by the European Council of Ministers.