Redcar was earmarked for a coastal nuclear waste dump beneath the North Sea under top secret plans drawn up in the 1980s, it has emerged.

An offshore site was one of 12 considered by Nirex, the company which manages the UK's intermediate-level radioactive waste, but later abandoned.

Details of the list, which include sites in Humberside, Essex and Cumbria, were finally disclosed yesterday under the Freedom of Information Act.

Nirex said that no alternative sites for the burial of nuclear waste were being sought in the UK and stressed that, should any selection of sites be made in the future, the list would not form a starting point.

But director of Friends of the Earth, Tony Juniper, said: ''It is an absolute disgrace that the location of these sites has been kept from the public for so long.

''Despite what ministers might say, Nirex has made it quite clear that each of the sites considered geologically suitable in the past could be considered suitable in the future."

A Nirex spokesman said the Redcar plan was a "generic concept" developed between 1987 and 1989. It had planned to construct an artificial island or rig off the North Sea coast, near Redcar.

Engineers would have then drilled through the sea bed where the waste would then be buried.

A site next to the ICI Teesside steelworks at Tees Mouth would have acted as a port to ship the waste in and out. The spokesman said international protocols had since made the burial of waste under the sea illegal.

Eric Empson, of Redcar and Cleveland Borough Council, said: "It is of great concern to us that such a study should have been carried out in secret without the knowledge of the local authority."

Jim Vaughan, a former Stockton councillor who was a member of Billingham Against Nuclear Dumping, said: "Governments make promises about things such as this and then change their mind and break them."