Law student Erol Incedal has been cleared at the Old Bailey of planning a terrorist attack.
Turkish-born Incedal, 27, was found not guilty after the jury deliberated for a total of 27 hours.
The court was adjourned briefly to allow the defendant to regain his composure as he began weeping as he thanked the jurors.
Most of the trial had been held in secret, and the details of the accusation can still not be reported.
It had previously been revealed that the address of a property belonging to Tony Blair and his wife Cherie had been found during a search of Erol Incedal’s car.
The judge told the jury there had been unusual arrangements regarding public attendance and reporting of the trial. These will be reviewed on Friday afternoon.
Last year, Erol Incedal was convicted of possessing a bomb-making manual on a memory card when he was arrested in October 2013.
He will be sentenced on Wednesday with Mounir Rarmoul-Bouhadjar, also 27, who admitted having an identical manual.
According to BBC home affairs correspondent June Kelly, the level of secrecy in the court hearings was unprecedented, with much of the evidence was heard behind closed doors.
The decision to hold so much of trial in secret is likely to come under scrutiny since the jury decided that the evidence they had heard did not prove the case against Ercol Incedal beyond reasonable doubt.
The Times’s crime and security editor, Sean O’Neill, was one of the few journalists who was permitted to hear some of the court sessions, and expressed grave reservations about the enforced secrecy.
He said: “There is a lot that we have heard in court that should not have been secret and should be aired in public and scrutinised.
“The key facts are there and I’m itching to write them.”