Awwal 24, 1432 H/April 28, 2011, SPA -- Each step has been rehearsed, each flower meticulously arranged, the aisle of Westminster Abbey transformed into a flowering green avenue of trees, AP reported. As Kate Middleton and best man Prince Harry had a final run-through inside the abbey where she will marry Prince William on Friday, a growing throng of curious tourists, dedicated monarchists, souvenir vendors, William-watchers and Harry-hunters turned the Union Jack-bedecked streets outside the iconic landmark into a scene of festive chaos. "It's a once-in-a-lifetime thing. Not many kings-to-be are going to be married anytime soon," said 26-year-old Sarah White of London, camping out across from the abbey with her sister, Liz. "Everyone's making friends and are in good spirits - or at least will be until tomorrow." The only clouds on the horizon: the threat of rain and the intrusion of politics, as the British government decided to revoke an invitation to Syria's ambassador to condemn his government's crackdown on protesters has left hundreds dead. Friday's ceremony has been planned like a military operation - which, in part, it is. Over 1,500 soldiers, sailors and air crew will be on ceremonial duty to line the couple's procession route between the abbey and Buckingham Palace, just under 1 mile (1.6 kilometers) away. An additional 5,000 uniformed and undercover police will be alert for threats from Irish dissident terrorists, Muslim extremists, anti-monarchists, royal obsessives and drunken hooligans. The royal wedding ceremony will offer pomp and circumstance on a grand scale, starting with a global guest list of 1,900 that includes kings and queens, sports stars, music royalty, university chums, Royal Air Force pilots and charity workers as well as friends and family. Royal carriages drawn by mounted troops of the Household Calvary will be rolling to the palace in a sweeping procession under fluttering rows of bold red, white and blue Union Jacks. Hundreds of thousands are expected to line the parade route, which has been scrubbed down by street cleaners. Westminster Abbey itself has been remade into a blooming forest, with six field maples and two hornbeams lining the aisle leading up to the altar. Royal officials said William and Kate have been intimately involved in planning their wedding day, from the music at the ceremony to the flowers to the cake - in fact, two cakes - that will be served to the guests. Kate opted for a traditional white-iced fruitcake while William made sure that was accompanied by his childhood favorite, a chocolate biscuit cake. Britain has not seen a royal celebration on this scale since 1981, when Prince Charles married Lady Diana Spencer at St. Paul's Cathedral.