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From Islamist and Irish republican militants to anarchists and crazed stalkers, British police appear to be facing a huge array of possible threats when Prince William marries Kate Middleton next week.
Hundreds of thousands of people are expected to throng the streets of London to cheer the bride and groom as they head to and from Westminster Abbey on April 29th.
But not all among the crowds may be wishing the couple the well. With the eyes of the world on London and dignitaries from around the globe in attendance, the event is seen as a prime target for militants, extremists and lone obsessives. "You've got the people who are publicity seekers, people who try to get on stage when there's a major international event going on," said Brian Paddick, a former senior London officer.
"You've got the people obsessed with the royal family. Perhaps some people who think this is their last chance to save William for themselves. Then you will have the most sinister, you will have people perhaps thinking about a terrorism spectacular," he told Sky News.
With Britain currently at its second highest threat level of "severe", meaning an attack is considered highly likely, the threat from militants is the most serious concern for police.
Security services have foiled a number of plots since the deadly July 7, 2005 attacks on London's transport system although police say there is no evidence militants have earmarked the royal event.
Officers have already begun covert operations and have been scouring the processional route for explosives. On the day itself, there will be very strict cordons in place and about 5,000 officers on duty. "London is seen as a potential haven or breeding ground for jihadists, and that threat is also going to be simmering below the surface and it's going to be in the mind of the British security services," said Scott Stewart, Vice President of Tactical Intelligence for political risk consultancy Stratfor.
The potential threat will not be limited to Islamist extremists. Attacks by nationalist splinter groups trying to end British control of Northern Ireland are at their highest level since a 1998 peace deal largely ended three decades of conflict.
Earlier this month, a police officer was killed when a booby-trapped bomb exploded under his car in Belfast and a week later police defused a 500-pound van bomb. While there have been no incidents on the British mainland since 2001, senior security officials say there is some indication the aspiration to do so was returning.
However, it is the suggestion that protesters or stalkers will try and ruin the couple's big day that has gained the greatest attention, in the media at least.
On Tuesday, radical Islamist group, Muslims Against Crusades (MAC), which has vowed to turn the day into a "nightmare", came to the fore when police revealed they had banned a proposed demonstration outside Westminster Abbey.
However, MAC may get permission to demonstrate elsewhere in the capital and a right-wing anti-Islamist group, the English Defence League, has vowed to stage a rival protest.
British newspapers have also reported that the police's Fixated Threat Assessment Centre, set up to protect high-profile figures from stalkers, has reported more than a dozen men and women have been warned off.
"From my background working as a protective intelligence agent on the details of (William's parents) Prince Charles and Princess Diana ... we learned in the United States that the British royals were essentially what we called 'nut-magnets,'" Stratfor's Stewart said. "The royal wedding is going to be quite a challenge because of the variety of actors, but of course, probably the most difficult to protect against will be mentally disturbed individuals."
Police say 60 people, accused of committing public order offences during a riot in the capital last month, had already been banned from central London on April 29th.
Officers are also conscious that a car carrying William's father Prince Charles and his wife Camilla was attacked during student protests in the British capital in December.
Newspapers have quoted alleged anarchist organisers who say widespread trouble is planned.
However, there appears to be little support for action on anarchist blogs and internet forums which suggested they would keep their powder dry for the G8 summit in France next month.
Radical London, a network of independent local anarchist and anti-capitalist groups, said those quoted in the papers should not be taken too seriously.
"There is nothing to be talked about except by anyone who is gullible enough to fall for this crap," Radical London said. "Anarchists generally have better/other things to do."