From Canadian Press, :
LONDON (CP) – The arrests of nine terrorist suspects in Britain and one in Canada last week began with a message intercepted by the National Security Agency in the United States that appeared to give instructions for an attack in the United Kingdom by al-Qaida commanders in Pakistan, The Sunday Times reports.
The newspaper says the message was received by computers at the NSA’s electronic eavesdropping centre in Maryland, which monitors millions of telephone calls and e-mails a day.
Police in Britain were alerted of the threat after the NSA analysed the automatic translation of the communication that The Sunday Times said was “thought to be between Britain and Pakistan.”
Once alerted, senior British police and intelligence officers, including David Veness, head of special operations at Scotland Yard, and Eliza Manningham-Buller, director general of MI5, set up Operation Crevice, the code name for the international anti-terrorist sweep.