Ministers are planning to strip clean a vitally important area of the seabed in the English Channel to satisfy the housebuilding boom in the South-east.
They are expected to authorise the mining of nearly 200 million tonnes of gravel from the Median Deep - a crucial nursery for fish, halfway between the Sussex coast and northern France.
An investigation by BBC1's Countryfile and The Independent on Sunday has revealed that the Government - which stands to make tens of millions of pounds in royalties - has already given its approval in principle to opening up new areas of the seabed.
The plans have caused outrage among fishermen on both sides of the Channel and among environmentalists, who say the Government risks breaking EU laws designed to protect fragile seabed habitats.
The sand and gravel de-posits of the Median Deep, which were deposited by ancient rivers when Britain was joined to the European mainland, provide an important habitat for carnivorous anemones, sponges, sea squirts and coral-like reefs, which are protected under EU law. These in turn provide fertile spawning grounds for crabs, shrimps, scallops, cod, plaice, bass, sole and herring, and so are vital to maintaining fisheries.
But sand and gravel - or aggregates - are also the main ingredient for concrete. And this will be needed in vast amounts for the 200,000 houses that John Prescott, the Deputy Prime Minister, plans to build in the South-east during the next two decades. Environmental protests and planning restrictions are making it increasingly difficult to mine these aggregates on land.
About half of the aggregates used in London and the South-east now come from the seabed, and this is expected to increase with Mr Prescott's building boom. But existing dredging grounds off the East Anglian coast and in the Thames estuary are close to exhaustion.
Now a consortium of six dredging companies wants to exploit the Median Deep and the Government is expected to give them the go-ahead. Mr Prescott's office has told the South-East Regional Assembly - responsible for minerals planning - that a minimum of 120 million tonnes of sand and gravel must come from seabed deposits.
And, according to the assembly's latest minerals plan, "this will largely depend on the granting of additional dredging licences ... in particular to exploit new resources in the east English Channel."
The companies are seeking 15-year licences to extract up to 177 million tonnes of aggregates, covering 80 square miles of the seabed. Seismic surveys have revealed total reserves of 250 million tonnes.
Ian Hepburn, regional policy director for the Wildlife Trusts, says: "What the Deputy Prime Minister is saying is, 'assume these licences will be granted' - yet we still haven't gone through the proper environmental impact procedures.
Lisa Browning, the trusts' marine conservation officer, adds that the life of the seabed would take decades to recover from the dredging, and might never do so. She says that if it goes ahead, the Government risks being hauled before the European Court for breaching the EU Habitats Directive.
Paul Joy, chairman of the Hastings Fishermen's Protection Society, adds: "It's far easier to say we'll dredge at sea because there aren't so many environmentalists who can see what is going on compared to if it was on shore," he says. "But the long-term implications are not being taken into consideration. We don't know enough about the area or the fisheries."
Dr Andrew Bellamy, of the British Marine Aggregate Producers' Association, accepts that some long-lived marine habitats may take many years to recover, but said that surveys suggested that these habitats were abundant in other areas of the Channel. "These impacts are manageable in that we're dredging very small areas at one time, and there's now a huge body of research which shows that dredged areas do recover."
A spokeswoman for the Deputy Prime Minister's Office said: "Dredging licences for the eastern Channel will not be granted unless we are satisfied that there are no adverse environmental impacts on the seabed, sea life or the coast. We work closely with the Department for Environment, Food and Rural Affairs, who have specialist environmental laboratories, and we also require from the applicants a coastal impact and environmental assessment. We do make estimates of future supply needs based on existing patterns of licences - but we are merely forecasting the potential for future supplies, we are not pre-empting any decisions over future licences."
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