A British judge on Thursday sent nine men to prison for al-Qaida inspired plots to bomb the London Stock Exchange and set up a terrorist training camp.
The British Muslims all pleaded guilty last week as their trial was due to begin at London's Woolwich Crown Court.
Mohammed Chowdhury, 21, Shah Rahman, 28, Gurukanth Desai, 30, and Abdul Miah, 25, admitted planning to plant a homemade bomb in the stock exchange toilets. Two others admitted lesser charges.
The prosecution accepted that the men, who were arrested in December 2010, intended to spread "terror and economic harm and disruption," rather than to kill, and had not constructed any bombs.
But they discussed attacking high-profile targets, and a handwritten list found at Chowdhury's home contained the addresses of London Mayor Boris Johnson, the Dean of St. Paul's Cathedral, two rabbis, the U.S. Embassy and the stock exchange
Judge Alan Wilkie said the defendants should be regarded as dangerous. He sentenced the six men to between five years and 16 years, 10 months.
Three other defendants admitted planning to set up a terrorist training camp in Pakistan and were given "indeterminate," or open-ended, sentences.
Wilkie said Mohammed Shahjahan, 27, Usman Khan, 20, and Nazam Hussain, 26 _ all from the central England city of Stoke-on-Trent _ "regarded themselves as more serious jihadis than the others."
He said the three men planned to set up and run a terrorist training camp in Pakistan, from which they and others would return "as trained and experienced terrorists available to perform terrorist attacks in this country."
The nine defendants, from London, Cardiff and Stoke, were brought together through radical Islamist groups and nurtured plans to attack high-profile targets.
Prosecutors said the men were not members of al-Qaida, but were inspired by the terror network and the sermons of its Yemen-based, American-born cleric Anwar al-Awlaki, who was killed last year in a U.S. drone strike.
British authorities learned of their plotting and put the men under surveillance before arresting them.
Deputy Assistant Commissioner Stuart Osborne, the national police counter-terrorism commander, said the "significant and complex" operation had involved 1,000 police officers and staff.
"We had a network of highly dangerous men based in three cities who were working together to plan terrorist attacks in the U.K.," he said. "Had we not taken action to disrupt this network, their actions could have resulted in serious casualties or fatalities."