Heightened security at this year's London Marathon has left spectators queuing to get past the finish line.
Hundreds of extra police officers have been drafted in to oversee the event after a terror attack at the Boston Marathon on Monday. Three people were killed and hundreds injured in two bomb blasts near the finish line.
The Metropolitan Police say the measure is meant to reassure runners.
The Boston bombings will not put off spectators or runners from taking part in tomorrow's London Marathon, the race's chief executive said.
Security has been stepped up for the 26.2 mile event in the capital with several hundred more officers set to line the streets for Sunday's marathon.
The race's chief executive Nick Bitel said: "After the terrible events in Boston we conducted a security review with the Metropolitan police and all the other agencies.
"As was announced yesterday, we have increased substantially the number of police officers who are going to be out there, going to be visibly reassuring people and putting in more search regimes and a number of other measures to ensure that it is as safe and fun as it always is."
He added: "I think the spectators won't be put off, we'll have a great day. There's some fantastic races, really competitive, and the numbers in terms of people running will be 35,500 - 36,000 as they would always be."
There will be an increased police presence at the London Marathon this weekend in the wake of bombings at the Boston event, the Home Secretary told MPs today.
Theresa May said adjustments to security arrangements had been made to this weekend's race after the fatal explosions that tore through spectators watching the race in the US on Monday.
Giving evidence to the Home Affairs Select Committee, Mrs May said, "They've made some adjustments to policing. They've put in some increased policing for the marathon".
"The London Marathon is a regular event, the organisers have a good record in terms of venue security, such as you can for an event that covers 26 miles", she said, adding, "We're very conscious of safety and security needs".
London is ready to host a safe marathon in the wake of bombings at the Boston event, Culture Secretary Maria Miller told MPs.
Ms Miller said the 2012 Olympics and years of experience demonstrated that the Metropolitan Police and other security services have an excellent record at ensuring sporting events on the streets of the capital are safe.
The Culture Secretary said, "You will know from London 2012 last year, this country has a great deal of experience of ensuring our sporting events go well and that security is at the heart of the planning process".
"The London Marathon is no different", she continued. "The Minister for Sport [Hugh Robertson] met with the mayor yesterday again to go through the plans to make sure ... that we have the right security procedures in place".
During a brief formal statement, she said, "I'm delighted this weekend's runners here in London, a number of whom are MPs... will be asked to wear a black ribbon as a sign of respect and solidarity. A period of silence will be observed before the race begins".