Woolwich Crown Court was shown Barot’s written notes from his reconnaissance exercises, reproduced on plasma screens around the courtroom.

Next to the word “Savoy”, he had written: “Rear easy & enclosed but deserted except for laundry room etc.”

The Berkeley hotel was also on his list. Next to it he had written: “ . . . dead end, left side, poss rec”. Other potential targets included the Hyatt Carlton, London Marriott, Dorchester and Lanesborough, all of which host heads of state and celebrities.

As Barot watched the proceedings unfold, another list was flashed up on the screens around the court, referring to three of London’s busiest mainline stations: Waterloo, King’s Cross and Paddington.

A note was jotted down next to each: “Water — OK with under but seems distant”, “Paddy — OK but very distant and open (extreme left side easy access)” and “King — OK for taxis only”.

As well as targets, police found detailed notes on “dirty bombs” at a house in West London. The series of deleted files were hidden like Russian dolls inside one another. One, called “Brad Pitt”, was hidden four levels down among deleted materials and was “devoted to the research of radiation”, Edmund Lawson, QC, for the prosecution , said.

There were other files hidden within that with names such as “Radioactive Children”. In that file police discovered a document entitled “Final Presentation” which again talked about dirty bombs. Mr Lawson said that the document was an explanation about RDD — radiation dispersal device.

The article said: “ . . . an RDD attack can produce general panic, health consequences including immediate fatalities and long-term increases in cancer incidence, long-term denial of property use, disruption of services and property and facility decontamination needs”. The court was told that Barot’s preferred tactic was the use of the radioactive isotope americium-241, be- cause it was found in smoke detectors.

The dangers of constructing an RDD are discussed. The files read: “To cause a large amount of radioactive contamination, we would be drawn toward very high activity sources.

“However, in order to prepare the source for effective dispersal by removing the shielding we would risk exposing ourselves to lethal doses. Even in suicidal missions we might not live long enough to deliver a highly radioactive RDD that uses gamma-emitting sources and is not shielded . . .

The author concludes: “ . . . a few grams of cobalt 60 with several pounds of explosives are enough to close an area the size of Manhattan. Unfortunately the carrier will be one of the many victims once the device has been emitted.”

Police also recovered hundreds of documents from computer hard drives, disks and memory sticks, with recipes for explosives and deadly poisons including ricin, botulinum and cyanide-based materials.

Mr Lawson said that there was overwhelming evidence to support the view that Barot was “the organiser of major terrorist activity designed to strike at the heart of both America and the United Kingdom, and to cause the loss of innocent human life on a massive scale”.

There was intensive security around the courthouse in southeast London as Barot appeared. Armed police patrolled the area and everyone entering court was X-rayed twice.

Seven men alleged to be Barot’s accomplices are scheduled to stand trial on identical charges in April next year. They deny all the allegations against them.

The trial continues.

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