Environment Secretary, John Gummer, made the announcement after it became clear that Nirex, the company planning an underground dump for most of Britain's radioactive waste, could not guarantee that radiation will not reach the surface.
The company is in disarray over whether it can prove its proposals are safe. A former top ministerial adviser, Professor Sir John Knill, has written to Mr Gummer calling on him to re-open the public inquiry. From 1987 to 1995, he was chairman of the Government's Radioactive Waste Management Advisory Committee.
Sir John advises the Secretary of State not to grant planning permission for the pounds 200m underground laboratory which Nirex is planning at Sellafield. It would pave the way for the full-scale repository taking most of Britain's radioactive waste.
He says he believes Nirex's studies into how water flows through the rocks at the site - which is crucial to its safety - had run into severe difficulties. The company now knew, but had not yet admitted, that the problems were much greater than was thought a few years ago and more test drilling was needed.
A planning inquiry into the proposed laboratory, headed by an inspector, took place last year. Mr Gummer now has the report, and has to decide whether to give the go-ahead. Nirex wants to start digging the laboratory as soon as possible.
But in the meantime, Cumbria County Council and Friends of the Earth have publicised a leaked internal memorandum to senior staff at Nirex indicating that much more data on the rocks is needed. Sir John's letter is a response to that leak.
The site at Longlands Farm, near Gosforth, is two miles from British Nuclear Fuel's reprocessing plant at Sellafield. So far Nirex has spent pounds 200m investigating the fractured volcanic rock beneath the surface, but the memo from the company's director of science, John Holmes, revealed that its computer modellers wanted between 10 and 100 times more data.
The scientists are concerned that without it they cannot reliably model the flow of water through the rock, which needs to be capable of containing the waste for 100,000 years. The worry is that contaminated water could rise to the surface.
Sir John's letter says: ``Dr Holmes' minute reflects a starkly different assessment of the likelihood of achieving an acceptable safety case for a deep repository ... as compared to any that has been published by Nirex previously.''
Michael Meacher, Labour's environment spokesman, said: ``Sir John's letter has exposed a history of complacency, misinformation and delay around the planning process for the underground laboratory.''Reuse content