The popular London Marathon is set to beef up its security preparations this year in the wake of the deadly Boston Marathon blasts, with more police presence and "quadruple checking" other security measures, including enhanced screening at registration points for Sunday's race.
Police are "double, triple, quadruple checking" security arrangements in advance of the race, said Deputy Prime Minister Nick Clegg to the radio station LBC 97.3.
London will have a 30-second period of silence before the start of the race Sunday in honor of Boston's victims. All runners will be given black ribbons to wear at registration, organizers said.
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"The police have looked ... further at their arrangements. I believe they have made a number of adjustments to the arrangements that will be in place for the event," said Home Secretary Theresa May, according to the BBC.
"But, of course, everybody wants to ensure that as far as possible people can come and enjoy an event which many people have obviously spent a very long time training for, and want to be able to raise substantial sums of money for charity," she said.
The marathon winds for 26 miles past some of London's most famous landmarks, and is set to attract a formidable field of international runners.
Some runners seemed annoyed by the tighter measures.
"They have taken our freedom which we normally have in races," Geoffrey Mutai of Kenya, a former Boston Marathon winner, told the Independent. "When you are in a race you are relaxed and you are enjoying yourself and free to go anywhere. But now there must be watertight security, they cannot be having as many people at the end of the race."
Wilson Kipsang, winner of the 2012 London Marathon, also from Kenya, said runners will still run freely.
"We would like to send our condolences to those people who lost their loved ones in Boston," Kipsang said to the Guardian. "We are preparing to compete but we are sorry because it was an athletics event and a very big race. I think in terms of security we are going to run freely. Something of that kind rarely happens. We are very sorry for what happened but there is security in place."
Senior Correspondent Corinne Purtill contributed reporting from London. Follow her on Twitter @corinnepurtill.