"Obviously, in light of what happened in Boston, we've had to have a look at security and we have a detailed and well-thought-out plan with the Metropolitan Police which we have year-in, year-out," London Marathon chief executive, Nigel Bitel, said.
"It's a great occasion, the London Marathon, and I know that people will want to come out and send a message of support to runners on the day."
Similarly, reigning marathon champion, Wilson Kipsang, told competitors to try and put security issues out of their minds as they wind their way along the 42 kilometer route from Blackheath to Buckingham Palace, home of the Queen.
"When you are running and you are thinking something like that can happen, you can't concentrate," the Kenyan told Athletics Weekly.
"We should have no fear during the race because security matters will be put in place and we will run feeling free."