A "POTENT cocktail" of nuclear waste from six countries has been imported to Scotland for storage, it has emerged.

Some of the radioactive material, which comes from countries including the former Soviet republic of Georgia, could be kept permanently in the UK.

Waste has also come from Belgium, Denmark, France, Germany and the Netherlands. Material from those countries is expected to be returned after reprocessing in Scotland.

All imported waste in Scotland is held at the Dounreay plant in Caithness, which green campaigners accuse of poor safety standards and regular leaks.

The varying national origins of waste stored in Scotland were revealed by Malcolm Wicks, the energy minister, in a written parliamentary answer last week.

Mr Wicks did not say precisely how much foreign waste had been brought into Scotland, only that the total was "less than one tonne".

The minister's revelation comes as the issue of storing nuclear waste figures prominently in Executive deliberations about future nuclear power stations.

While ministers in London, including Mr Wicks, are expected to authorise a new generation of British reactors later this year, Scottish ministers have said they will block any new plants in Scotland until a credible long-term answer to storing nuclear waste is found.

"Other than material removed to the UK for international security reasons, material is stored for a period as agreed with the customer," Mr Wicks said of the material at Dounreay.

A spokesman for the United Kingdom Atomic Energy Authority said the waste from other European Union countries would therefore be returned after a 25-year storage period, although some had already been reprocessed and recovered uranium and waste sent back to the point of origin before the last of Dounreay's reactors closed in 1994.

The spokesman added: "Keeping the waste from Georgia at Dounreay is a much safer option in global terms than keeping it in Georgia, which is an unstable country."

The spokesman said he could not discuss individual contract income. But the total income at the site was around GBP 2 million a year, most of it from the nearby Royal Navy nuclear site.

He added that the amount of waste was "a very small proportion" of the 100 tonnes of spent fuel and between 10,000 and 15,000 tonnes of "intermediate level waste" at the Dounreay site.

In 1998, there were protests from green groups as five kilograms of nuclear material was sent to Dounreay from Georgia in a British government deal with the United States.

Under an agreement Washington brokered with several former Soviet republics, nuclear material was permanently removed to the West to avoid it falling into the wrong hands.

The Georgian material was said to be highly enriched uranium, which can be used to make a nuclear weapon. It was sent to Dounreay because the plant is one of the few in the world that can deal with the material.

There are two reprocessing plants at the Dounreay complex: a mixed oxide plant for reprocessing fast reactor-type fuel such as that from EU countries and a smaller materials testing reactor plant, which handles weapons-grade uranium like the material from Georgia.

The information about current waste storage was obtained by Alistair Carmichael, the Liberal Democrat MP for Orkney and Shetland. He said yesterday that the waste held at Dounreay was more proof that ministers should reject plans for new reactors.

"It would be folly to go ahead with a new generation of nuclear power stations until we have dealt with the problem of nuclear waste," he said.

"The fact that we continue to hold a potent cocktail of waste from other countries suggests that not only have we not found the answer, but no-one else has, either."

George Baxter of the Scottish Green Party, said: "Our nuclear waste problem is big enough without importing more - building more nuclear power stations will only make matters worse."

Duncan McLaren, chief executive of Friends of the Earth Scotland, criticised Dounreay's "terrible" safety record. "Countries that generate nuclear waste should not be allowed to dump it on others," he said.

Since 1983, more than 900 particles - fragments of irradiated nuclear fuel - have been found on the seabed and 238 on the enclosed beach at Dounreay.