A NUCLEAR attack by terrorists causing widespread panic, chaos and death is inevitable and will happen soon, a senior Scottish police officer has warned.

Ian Dickinson, who leads the police response to chemical, biological and nuclear threats in Scotland, has painted the bleakest picture yet of the dangers the world now faces.

Efforts to prevent terrorist groups from obtaining materials that could be made into radioactive dirty bombs - or even crude nuclear explosives - are bound to fail, he said. And the result will be horror on an unprecedented scale.

"These materials are undoubtedly out there, and undoubtedly will end up in terrorists' hands, and undoubtedly will be used by terrorists some time soon," he declared. "We must plan for failure and prepare for absolute terror."

Dickinson is assistant chief constable with Lothian and Borders Police, and has responsibility through the Association of Chief Police Officers in Scotland for protecting Scotland from chemical and nuclear attacks. He has been closely involved in co-ordinating the country's counter-terrorism response.

He said: "An incident will continue for days and all the public will see is people dying without reason. What will we do when our children come home from school with blisters on their skin and their parents don't know what to do?

"What happens if 10 deaths, 50 deaths, 100 deaths start occurring in an unconnected and random way all over the country? The public will be rightly and understandably terrified."

Casualties caused by radiation, which most people don't understand, would trigger widespread "panic and fear", said Dickinson. And the response of the emergency services "would be chaotic" because of a shortage of resources.

The police capability for dealing with the chemical, biological, radiological and nuclear threat - known as CBRN - needs to be increased, he argued. "I haven't got as many officers with protective equipment as I would like," he added. "We must prepare for the worst."

Dickinson delivered his dire warnings to an international conference in Edinburgh last week. More than 300 experts from 70 countries were taking part in a high-level meeting organised by the UN International Atomic Energy Agency on the risks of nuclear terrorism.

The police response to a CBRN incident when it happened would have a "profound effect on our communities which should not be underestimated", he said. The protective clothing that officers would have to wear would look "terrifying".

As Dickinson made the point in his speech on Wednesday, one of his fellow police officers appeared dramatically on the stage dressed head to toe in a regulation black protection suit. With his face completely obscured by a gas mask, the officer then walked slowly through the delegates seated in the Edinburgh International Conference Centre.

Decontamination after a radiation attack would be an "enormous cost", Dickinson contended. It would far exceed the multi-million pound bill for cleaning up the 50 premises contaminated with polonium-210 after the poisoning of the former KGB agent, Alexander Litvinenko, in London last year.

There would also be a huge drain on resources from having to reassure many people who were unharmed but worried. The additional monitoring and clean-up work would be "a major problem", he said.

Worldwide efforts to stem the spread of radioactive materials by the governments represented at the conference were vital, Dickinson concluded. "But the sad fact is that your work will fail."

Dickinson's nightmare analysis was backed up by Dr Frank Barnaby, a nuclear consultant who used to work at the Aldermaston Atomic Weapons Establishment in Berkshire. "The amazing thing is that this hasn't happened already," he told the Sunday Herald.

"We should expect it any minute. It's an obvious thing for a terrorist to do. A primitive nuclear explosion would simply eliminate the centre of a city like Glasgow or Edinburgh."

The Edinburgh conference heard a series of other warnings about the risks of radioactive materials being stolen and used to cause devastation.

"As the terrorists look for the next spectacular attack, we know that al-Qaeda in Iraq is calling on nuclear scientists to join in the jihad," said William Nye, director of counter-terrorism and intelligence at the Home Office in London.

Richard Hoskins, from the International Atomic Energy Agency's Office of Nuclear Security in Vienna, revealed that there had been 1266 confirmed incidents in which radioactive materials had been stolen or lost around the world since 1993.

Most involved radiation sources that could be made into dirty bombs, although in 18 instances small amounts of bombs-grade uranium or plutonium had been seized.