London ? An al-Qaida operative captured in Britain planned to bomb the New York Stock Exchange and plotted a series of murderous attacks on London, including a scheme to blow up a London subway train as it passed below the River Thames, prosecutors said Monday.

Dhiren Barot, 34, pleaded guilty last month to conspiring to commit mass murder in terrorist plots on both sides of the Atlantic.

He faces a life sentence in Britain, but he also is wanted in the United States and Yemen on separate terror-related charges.

The Muslim convert and a gang of seven alleged accomplices spent more than four years making detailed plans to attack a host of financial industry targets in the United States, while also plotting to detonate limousines packed with explosives in the underground garages of famous London hotels and train stations.

Prosecutor Edmund Lawson said the group had proposals to use a radioactive “dirty bomb” and to ignite a gasoline tanker, ramming it into a high-profile British target.

Lawson showed clips of a reconnaissance video taken during a 2001 visit to New York by Barot.

The shaky footage – shown on large screens in the courthouse – zoomed in on the World Trade Center as an unseen man mimicked the sound of an explosion. However, prosecutors said Barot did not have prior knowledge of the Sept. 11, 2001, terror attacks that killed an estimated 2,973 people.

“It is memorable for its macabre prophecy,” Lawson said at the two-day sentencing hearing at the high-security Woolwich Crown Court in south London.

He said since 1995 Barot had trained at terrorist camps in Pakistan, the disputed territory of Kashmir, Malaysia and the Philippines – crisscrossing the globe to refine skills with weapons, bomb-making and chemicals.

From 2000, Barot plotted for a “memorable black day for the enemies of Islam,” Lawson said, claiming he was a member or close associate of al-Qaida.

Flanked by two court guards, Barot sat expressionless behind a glass-walled dock, taking copious notes as Lawson detailed the case against him.

Born in India but raised in Britain since 1972, Barot became the “organizer of major terrorist activity designed to strike at the very heart of both America and the United Kingdom,” Lawson said.

He said the suspect’s plans were designed to kill “hundreds if not thousands of innocent people without warning.”