The jury was read statements from seven interviews with Shrimpton in which he claimed his intelligence credentials included helping to capture Osama Bin Laden.
Shrimpton was interviewed between April and December 2012 and made numerous claims about intelligence he had received relating to the claimed impending terrorist attack and previous cases.
He told officers he did not communicate a specific threat, but said the intelligence he had received was credible and growing.
He claimed that threats began over “internet chatter”, monitored by contacts of his who were computer scientists connected to Cambridge University, which spoke of a nuclear device being stored in London ahead of a planned attack on the 2012 Olympic Games opening ceremony in the week preceding April 19 and 20, 2012.
He said he had then undertaken a 10-day investigation, codenamed Operation Vulcan, pooling information from sources including retired intelligence agents, nuclear scientists and others with Government and high-level connections, which had “firmed up” the threats.
Shrimpton said he had previously received reports of the Iranian government planning to smuggle a South African nuclear warhead down the River Thames in a submarine.
Mr Blake told the court Shrimpton said to officers: “The Iranian threat had been a real concern but they had backed down following back channel communications to Tehran that it would spark a nuclear exchange.”
He said reports of the second threat, organised by the German secret service, Deutsches Verteidigungs Dienst (DVD) using a stolen Russian warhead, came to light in the following days. Information suggested the half-megaton weapon would kill everyone within a five-mile radius of the detonation site, thought to be in East London.
Shrimpton also claimed that DVD agents had infiltrated Thames Valley Police and his arrest had “generated a 12-hour window during which the device could be exfiltrated” from its hiding place - namely along the Blackwater Estuary in Essex and across into Germany.
Mr Blake said: “He told officers he had a small involvement in Bin Laden being taken out as he had passed on intelligence about his safe houses.”
The court heard evidence from Andrew Todd, security liaison officer at Buckingham Palace, who said Shrimpton had written to the palace on April 23, following his arrest.
The letter, purporting to be from a solicitor but in fact written by a legal charity and addressed to the chief constable of Thames Valley Police, the Ministry of Defence, the Kremlin and National Security Association, said The Queen was no longer under threat and the device may have been moved to Ground Zero in Manhattan.
Mr Todd said he had passed the letter on to the confidential inquiries team at Buckingham Palace but had not taken the threats seriously due to Shrimpton’s manner.
He revealed that a search of the Palace’s correspondence database showed Shrimpton had also contacted officials about the disappearance of Madeleine McCann.
Paul Farmey, who worked at New Scotland Yard’s Olympic Intelligence Centre, said a search of the Metropolitan Police’s open-source intelligence database revealed no reports of terrorist threats in April 2012.
Shrimpton argued that a Google search about terror attacks at the London Olympics gave more than four million results.
He said both Mr Todd and Mr Farmey had no international intelligence experience and said contacts in his address and phone books showed he was in connection with high-ranking officials at Buckingham Palace in the past.