A civilian police worker at Scotland Yard has been jailed for eight months for leaking confidential details on terrorism to a newspaper.
Mr Lund-Lack was working for the Met's counter-terrorism unit
Thomas Lund-Lack, 59, who was working in the Metropolitan Police's counter-terrorism unit, disclosed a document to a Sunday Times journalist.
An article in April said Iraq-based al-Qaeda leaders were planning UK terror attacks.
He had earlier pleaded guilty to misconduct in a public office.
Sentencing Lund-lack, a retired detective inspector, Mr Justice Gross said: "Disclosure of this nature should and ought to attract immediate custody.
"I shall impose such a sentence in this case with no little sadness but equally no hesitation."
He added: "Mr Lund-Lack will understand the need, as anyone in court will understand, that to protect your free society it is essential that some intelligence must be kept secret.
"Secrets must be kept and they cannot be kept if an insider breaks his bond of secrecy."
'Silly old man'
Lund-Lack, of Stowmarket, Suffolk, was arrested after the Sunday Times published an article saying al-Qaeda leaders in Iraq planned "large-scale attacks" in Britain and the West aided by supporters in Iran.
While being interviewed he said his actions were those of a "silly old man" who had become "more and more angry" about the effectiveness of the Met's counter terrorism command.
He admitted he had done wrong but said he felt morally justified in trying to bring his concerns to the public's attention.
The maximum sentence for the charge of misconduct in a judicial or public office is life.