London Race: Tributes to Boston, Extra Security The London Marathon started in defiant mood on a glorious sunny morning Sunday despite concerns raised by the bomb attacks on the Boston Marathon six days ago. Thousands of runners offered tributes to those killed and injured in Boston. The race began after a dignified moment of silence for the victims in Boston, and many wore black armbands as a sign of solidarity. "It means that runners are stronger than bombers," said Valerie Bloomfield, a 40-year-old accountant from France just before she started the marathon. Most participants said they weren't worried by the Boston bombings, and the impressive turnout of enthusiastic fans lining the routes showed the same spirit, but one runner acknowledged an undercurrent of anxiety. "It definitely affects us," said Chris Denton, a 44-year-old engineer who was stretching his legs by the start line. He said he'd been concerned enough to ask that his family not come out to support him because of a possible copycat attack. "I left them at home," he said. If only for my peace of mind. His friend, 45-year-old David Wilson, said there was no question of canceling the marathon. Londoners had come back onto the streets the day after the lethal July 7, 2005, transit system bombings and weren't easily cowed. "You can't not do anything, because otherwise you'd stay on the outs all the time," he said. Tomasz Hamerlak of Poland, who finished 4th in the men's wheelchair race, competed in Boston last week but was determined to race in London as well. "It is terrible what happened in Boston but we can't look back, we must look forward," an out-of-breath Hamerlak told The Associated Press moments after crossing the finish line. The show must go on. Moments before the majority of runners set off on the grinding race, announcer Geoff Wightman used the loudspeakers to ask for silence. He described marathon running as a global sport that unites runners and supporters in every continent in a spirit of friendship. "This week the world marathon family was shocked and saddened by the events at the Boston Marathon," he said. In a few moments a whistle will sound and we will join together in silence to remember our friends and colleagues for whom a day of joy turned into a day of sadness. Blackheath, where the runners were gathered, fell silent. The only noise was the buzz of helicopters and the rumble of a distant truck. Runner Martin Connell, 42, wore a picture of 8-year-old Boston bombing victim Martin Richard on his jersey in tribute to his young namesake. "It's a sign of peace and goodwill," said the runner, an IT worker from near Liverpool. Some 36,000 runners are expected to take part in the race, which also draws tens of thousands of spectators. Police said they planned to add 40 percent more officers and extra surveillance as a precautionary measure. Security was plentiful but not intrusive near the finish line at the Mall in front of Buckingham Palace. It was mostly good-natured, as it was at the London Olympics. Marathon staff, officials and media had their bags thoroughly checked as they entered security, which wasn't deemed necessary at the event last year. Officials said this was in response to the Boston attack.