It's not the type of welcome most wedding guests expect before they get into church — background checks, ID verification and a security sweep.

大多数参加婚礼的宾客都不希望在进教堂前受到如此接待——接受背景审查、身份认证，还有安全扫描。

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（队伍，行列） 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, but it also presents a modern security nightmare for the 5,000 U.K. police officers on duty.

A wide range of police will be on patrol for as the couple ties the knot 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 the anticipated kiss.

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 celebrities¹, charity workers and friends and family of the royals — will have their identification checked and go through a security screening before entering the abbey（大寺院） . Some of the guests have also gone through cursory²（粗略的，草率的） background checks.

"They will go through a significant search regime," Commander 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.

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 Celsius³ (mid-60s Fahrenheit).