Judgment is expected before Christmas in a big environmental claim before the High Court.
Industrial group Blue Circle is suing the Atomic Weapons Establishment (AWE) for damages under the Nuclear Installations Act, for allegedly con- taminating land owned by the company with nuclear material.
The property in the dispute is an estate which includes offices and a conference centre next to the AWE at Aldermaston.
Antony Edwards-Stuart, who is counsel for the company, told Mr Justice Carnwath that a pond on the AWE's land burst its banks during a 1989 storm, flooding marshes and a lake on Blue Circle's land.
He said that as a result of the flooding 1,000 cubic metres of soil contaminated with plutonium 1,000 times greater than normal background levels were excavated from the estate after the incident.
Despite that, the contamination is said to have continued and to have prevented sale of any property on the estate.
The court was told that the Ministry of Defence did not reveal details of the contamination until three-and-a-half years after the flood and at a time Blue Circle was closing the sale of the estate for £10 million. The sale fell through.
Samples of marsh and lake sediments on Blue Circle land have revealed plutonium contamination hot spots of about four times the permitted level.
Mr Edwards-Stuart told the judge that no prospective buyer would touch land contaminated in this way with a barge pole.
Blue Circle is seeking damages for loss of the ability to sell its site, along with an indemnity in respect of any future claims that may be made against the company in respect of the contamination.
But the AWE claims that the contamination levels pose no serious threat.