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PAISLEY DODDSAssociated Press
"The (U.K.) terror threat is currently at severe but if we know of a specific plot likely to occur it could be raised to critical," a British security official said, speaking on condition of anonymity because of the sensitivity of his job. He declined to discuss specific threats.

All of Britain's security agencies will be comparing intelligence in the run-up to the wedding: the MI6 with its foreign intelligence, the MI5 for domestic security and the GCHQ, the country's eavesdropping agency.

Some protesters used Twitter and other social media sites over the weekend to promise more mayhem on the day of the wedding. Anti-monarchists also said they plan to have a presence near the Abbey next month.

"You're looking at a different type of threat," Broadhurst said, calling the threat to the royal wedding, "a threat to democracy."