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Al-Qaida planned large-scale U.K. attacks

New details about an al-Qaida plot to stage dramatic and deadly attacks on high profile targets in England are emerging just as British Prime Minister Tony Blair asks for asks for new legal authority to combat terrorism. NBC's Pete Williams reports.

Intelligence officials now confirm that among the potential targets considered for attack by terror plotters was the United Kingdom’s tallest office tower in London. They also tell NBC News that suspected al-Qaida terrorists were actively trying to recruit pilots to hijack planes in smaller European cities and crash them into London's Heathrow Airport to disrupt international travel.

According to the new information, the plan called for attacking as many as half a dozen targets, including prominent buildings in the city's financial center, London's vast subway system and potentially even its Houses of Parliament and the centuries-old Westminster Abbey.

The plan was actually broken up last March, when British police staged a sweep and discovered half a ton of the kind of fertilizer that can be used to make bombs.  But only now is the full scope of that plot coming to light.

"There are people awaiting trial for various terrorism offenses relating to al-Qaida activities," says Con Coughlin, a British terrorism expert. "And until they come to trial, the prosecuting authorities wanted to keep this under wraps."

NBC News has learned that a key development in the British prosecution is cooperation from Mohammad Babar, an American arrested in the U.S. Babar has admitted meeting top al Qaida operatives in Pakistan and buying some of the explosives for the U.K. plotters.

The British revelations come just as Blair's government asks for new legal powers to fight terrorism — a program endorsed Tuesday in Queen Elizabeth’s annual message to Parliament.

"My government recognizes that we live in a time of global uncertainty with an increased threat from international terrorism and organized crime," said the Queen.

Blair denies allegations from political opponents that he's trying to stir up fear in anticipation of elections in the spring.

Intelligence officials say that while the U.K. plotters did not settle on final targets before they were arrested, their plans were disturbingly close to being carried out.