Mass panic was aim of £70,000 dirty bomb

The full details of Dhiren Barot's plot to set off a radioactive "dirty bomb" containing smoke detectors was revealed yesterday. At a cost of £70,000, Barot, 34, proposed building a bomb that would cause radiation sickness in about 500 people and produce mass panic.

The Muslim extremist suggested setting off the bomb incentral London, or a city in Spain or the United States, Woolwich Crown Court in London was told yesterday.

Edmund Lawson QC, for the prosecution, said that the plan appeared to have been based on an incident in France when a lorry carrying 900 smoke detectors crashed, provoking concern about possible exposure to radiation - the detectors contained small amounts of radioactive material.

In a terrorist document Barot wrote: "If something so small and simple such as 900 burning smoke detectors could cause so much havoc, then by increasing the amount used, the possibilities are good."

He suggested in his presentation document to al-Qa'ida leaders that the radiation project should use around 10,000 smoke detectors and either "set them alight" or "place them on top of an explosive device".

His proposal also contained research into the possible effects of the radioactivity released if such an attack was carried out, including the long-term risks of cancer and infertility.

Barot speculated that such a dispersal of radiation could cover a large area. He wrote: "The burning has the potential to affect around 500 people... as soon as we realised this... we concluded that it deserved to be an independent project in its own right."

He said the bomb would cost £50,000, with each smoke detector costing £5. He thought £20,000 might be needed for storage, bringing the total cost to £70,000.

In other suggestions, Barot discussed the consequences of train crashes and referred to the carnage caused following the Ladbroke Grove accident, the court heard. Barot wrote: "For some time now we have had thoughts on executing a project on a busy train network. Moreover, I have a personal friend who is a train driver. Every so often he takes a friend on to his train in the driver carriage with him just for the sake of company."

The document also contained Barot's comments on the Heathrow Express, where he speculates that gas could be leaked into the train during the day because it was relatively quiet.