THE London Marathon will definitely go ahead on Sunday but security is under heavy scrutiny in the wake of the Boston bomb.
Britain's double Olympic champion Mo Farah is one of 36,000 runners set to compete in the 26-mile London race, which starts at Greenwich Park and winds through some of the city's iconic landmarks before finishing at the Mall.
"We will be reviewing our security arrangements in partnership with the London Marathon," Metropolitan Police chief Superintendent Julia Pendry said in a statement.
The London race was first run in 1981 and has become a centrepiece of the sporting calendar in Britain with elite athletes being joined by the vast number of amateur runners who compete to raise money for charity.
"We are deeply saddened and shocked by the news from Boston," London Marathon chief executive Nick Bitel said in a statement.
"Our immediate thoughts are with the people there and their families. It is a very sad day for athletics and for our friends and colleagues in marathon running.
"Our security plan is developed jointly with the Metropolitan Police and we were in contact with them as soon as we heard the news," said Bitel.