London ? On a day when the Tour de France made a rare start in Britain and riders sped past Parliament and Buckingham Palace, the shadow of drugs remained inescapable in cycling.

Switzerland's Fabian Cancellara passes in front of St. Stephens Tower and Big Ben during the prologue of the Tour de France. Cancellara recorded the fastest time in the prologue Saturday in London.

Switzerland’s Fabian Cancellara won the prologue Saturday as the sport’s premier event began amid heavy security and with a distinct British accent.

A competitor passes in front of Buckingham Palace in London on Saturday during the Tour de France prologue.

Cancellara, the world time-trial champion who also won the Tour prologue in 2004, completed the 4.9-mile race through downtown London in 8 minutes, 50 seconds. He is strictly a time-trial rider and is not expected to compete for the title in the three-week race.

“I am really happy, that’s for sure,” said Cancellara, who will wear the leader’s yellow jersey for Sunday’s first stage from London to Canterbury. “I will do the maximum to defend it.”

Andreas Kloeden of Germany was 13 seconds behind. George Hincapie of the United States was next, 23 seconds off the pace. Britain’s Bradley Wiggins, looking to bring the home fans a victory, was fourth among the 189 riders in the race against the clock.

The prologue took place two years to the day after suicide bombers killed 52 people on London’s public transit network and as the country confronts a new wave of terrorism. Hundreds of police were deployed.

Cancellara’s victory clearly brightened the mood of his team. Bjarne Riis, the manager of Team CSC, said he would stay home this year. In May, he jolted cycling by admitting he used the banned performance enhancer EPO on his way to winning the 1996 Tour. That immediately turned him into an outcast of sorts among race officials.

“What’s really hard is when we saw that he’s not with us on the Tour, but everybody’s holding up,” Cancellara said. “Today was a very important day for the team.”

“There are a lot of problems in cycling, but I want to look to the future,” Cancellara added. “And if you keep looking back at the past, of course, it’s hard.”

Cycling has been battered by doping scandals, accusations and admissions the past year. And that’s saying a lot for a sport linked to widespread use of banned drugs for decades.

Riis is not alone in sitting out this year. Others excluded or not attending this Tour are: sprint ace Alessandro Petacchi, Team Milram boss Gianluigi Stanga, Astana riders Matthias Kessler and Eddy Mazzoleni, Tinkoff riders Joerg Jaksche and American Tyler Hamilton.

Tour officials, fearing that fans will turn away, required all riders to sign a new International Cycling Union anti-doping commitment. Riders pledged that they are not involved in doping and promised to submit DNA samples to Spanish authorities in the Operation Puerto investigation that began last year. Cyclists also had to agree to pay a year’s salary on top of a two-year ban if caught doping.

“Doping is the enemy of cycling,” Tour director Christian Prudhomme said. “Sport is a reflection of society, and there are wonderful people involved in cycling.”

As stage winner, Cancellara was automatically tested for doping, though the results will not be known for several days.

After last year’s Tour, Floyd Landis tested positive for synthetic testosterone, an accusation the American has repeatedly, and at times clumsily, denied. An arbitration panel is considering whether Landis should lose his title after the positive test following his dramatic victory in the 17th stage last year. He claims he’s been wronged by a French lab.

While the Tour has twice come to Britain, the London debut was a first. Organizers, looking to make a clean start, clearly hoped to draw on the novelty and the enthusiasm of British fans.

The last time the Tour went through Britain was in 1994, when an estimated 2 million people crowded the route. Thousands turned out this year, many in support of local favorites.

“For five, six, eight minutes, all I could hear was ‘David! David! David!”‘ said Britain’s David Millar, who finished 13th. “It was magnificent.”

The overall favorites include Kloeden, teammate Alexandre Vinokourov of Kazakhstan, Levi Leipheimer of the U.S., Cadel Evans of Australia, Denis Menchov of Russia, Christophe Moreau of France and Spanish riders Alejandro Valverde, Oscar Pereiro and Carlos Sastre.

The Tour will cover 2,120 miles and feature six mountain hikes, three summit finishes and two individual time trials. In the prologue, with riders setting off one by one, the field whirred past classic London landmarks and through Hyde Park.

Cancellara was followed by Kloeden, who was third in the 2006 Tour and was runner-up to Lance Armstrong in 2004. Kloeden is a newcomer to the Astana team, which was ousted from the Tour last year after five of its riders turned up in the Puerto file. Hincapie, a former Armstrong lieutenant, was runner-up by a split-second in last year’s prologue.