LONDON — It’s not the type of welcome most wedding guests expect — ID checks and a tough security sweep before entering the church.

But then again, Prince William and Kate Middleton’s wedding on Friday is no ordinary affair.

Britain hasn’t seen a royal wedding of this size since Prince Charles married Diana in 1981 — there were actually 200 more police on duty for that wedding, which had a longer procession route and a guest list of some 3,500 people, including foreign royals and heads of state.

Friday’s wedding will offer much of the same pomp and circumstance with its 1,900 invited guests. Still, it presents a modern security nightmare for the 5,000 U.K. police officers on duty, who will be on the lookout for Irish dissident terrorists, Muslim extremists, anti-monarchists, protesters and ordinary riffraff who might blight the royal spectacle.

Scotland Yard Police Commander Christine Jones said Wednesday there has been no new terror threat but considerable Internet chatter.

"Our operation has been meticulously planned, and we have thought through and planned for a huge range of contingencies," she said.

A wide range of police will be on patrol Friday: officers on motorcycles, escort specialists, dog handlers, search officers, mounted police, protection officers and firearms units, although only a fraction of Britain’s police officers are armed.

Thousands of people are expected along the parade route Friday, a snaking path of less than a mile from Westminster Abbey — an iconic cathedral near London’s Big Ben and Parliament buildings — to Buckingham Palace, where the new royal couple will appear on the balcony for one of the most anticipated kisses in decades.

Police helicopters buzzed over London before dawn Wednesday during a dry run — a rehearsal that saw army, navy and air force personnel in full uniform lining the parade route. Starting at 5 a.m., the troops timed their roles to the second for Friday’s performance, and mounted troops of the Household Cavalry escorted a horse-drawn carriage.

The royal couple did not attend, but they did visit the abbey for a private, final rehearsal late Wednesday. St. James’s Palace said William, Middleton, best man Prince Harry and the bride’s parents joined senior clergy at the abbey for a last run-through, and as their car convoy headed out they were cheered on by hundreds of excited tourists.

Some spectators still got up extra early to watch the military preparation.

"I can’t believe how wonderful it is," said Heather Cameron, a 53 year-old London resident. "Nobody does pomp and ceremony like the Brits do."

Britain has seen several major terror attacks and plots since the Sept. 11 terror attacks in 2001. The deadliest came in 2005, when homegrown terrorists killed 52 commuters during London’s rush hour — Europe’s first suicide bombing. In 2006, terrorists in Britain tried to down several trans-Atlantic airliners using liquid explosives. The following year, two major terror plots were thwarted outside a London nightclub and at an airport in Scotland.

London has also seen large protests recently against the Conservative-led government’s austerity plans, which aim to cut 310,000 government jobs and sharply hike university tuition fees. Prince Charles and his wife Camilla were shaken up when their car was attacked in December when a student protest turned violent.

A group called Muslims Against Crusades said Wednesday they wouldn’t protest the wedding but urged Muslims to stay away from central London and public transport because of the possibility of an attack. Leader Asad Ullah said the warning was general and not based on any intelligence.

Many Muslims have voiced anger over Britain’s involvement in the Iraq war and the fact that Prince William’s younger brother Harry served in Afghanistan. Prince Harry will be the best man at the wedding.

British police have special stop-and-search powers now if they think people in the crowds are carrying something suspicious. Some 60 people have already been banned from the parade route Friday and both uniformed and undercover officers will be in the crowds or on rooftops.

 The wedding guests — kings and queens, sports and entertainment celebrities, charity workers, RAF pilots, and friends and family of the royals — will have their identification checked and go through a security screening before entering the abbey.

"They will go through a significant search regime," Commander Jones said, declining to elaborate.

Although Britain’s security threat level remains the same, there has been an increased threat from Irish Republican Army splinter groups opposed to the peace process. A masked man from the Real IRA said Monday the queen was wanted for war crimes in Ireland and his group would oppose her visit next month. He made no specific threat to disrupt the royal wedding.

 Police said they did not consider the threat from Northern Ireland significant.

"This is a day of celebration of joy and pageantry, especially in celebration of Great Britain and our royal family," Jones said.

Police said security around London’s subway network will be boosted, while policing at Heathrow, Europe’s busiest airport, will be as normal.

In October, the U.S. State Department advised Americans to be wary amid reports that terrorists were planning a Mumbai-style attack on a European city. More than 160 people were killed in that 2008 attack, when gunmen fired on crowds in a shooting spree that paralyzed India’s business capital for days.

"That threat is still being investigated but there is no intelligence to suggest a highly organized threat to the royal wedding," a western

intelligence official told The Associated Press, speaking on condition of anonymity because of the sensitivity of his work.

Organizers said Wednesday’s dress rehearsal went without a hitch, and some who watched felt a shift in the mood in London.

 "It’s building," said Brenda Jacobsen, who was on her way to work. "It’s always great to hear the bands play. Very emotional, traditional — and that’s Britain for you."

 The royal bride, however, might be hoping for a shift in the weather.

Forecasters predict a 70 percent chance of rain Friday for London. The Meteorological Office says there will be a mix of showers and dry spells, a cool breeze and temperatures in the high teens Celsius (mid-60s Fahrenheit).

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Greg Katz, David Stringer and Toby Goode of the Associated Press contributed to this story.