By DPA
London : Still tense after the British police prevented a potentially bloody terrorist attack, the city of London Friday officially opened the 2007 Tour de France, which began Saturday with a grand ceremony in Trafalgar Square.
Security was tight when the 189 riders from 21 teams were presented to a crowd estimated at 20,000, as the world's most prestigious cycling event makes its third appearance in Britain. However, this year is the first time the Tour has started here.
The riders then paraded along Whitehall and rode passed 10 Downing Street, home of new British Prime Minister Gordon Brown.
Although the terror alert level was lowered Wednesday, some 5,000 police officers were to be deployed in the streets of London for Saturday's prologue, a 7.9-km individual time trial, the French daily L'Equipe reported.
Two British riders, David Millar and Bradley Wiggins, were among the favourites to win the prologue and wear the race leader's yellow jersey for at least one day.
Another rider from Britain, Tour novice Charlie Wegelius, told the spectators: "This is what I've dreamed about since I was a boy. To start my first Tour de France in Britain is the best I could hope for."
London Mayor Ken Livinstone sees the Tour's visit to Britain and its capital as a major triumph, calling the race's Grand Depart "the biggest sporting event hosted by London ahead of the 2012 Olympics".
"London is already famous across the world for hosting world-class events. I believe this will be the most spectacular Grand Depart the Tour has ever seen and the weekend will underline London's great sporting reputation," he said.
The three-week race covers 3,570-km in Britain, Belgium and France, with a very brief excursion into Spain. It ends July 29 on the Champs Elysees in Paris.