The number of police guarding the London Marathon has been boosted by 40 per cent in the wake of the Boston bombing, Scotland Yard announced today.
Several hundred extra officers will be on duty on Sunday in an attempt to calm fears following the terrorist atrocity which left three dead and more than 170 injured.
Chief Superintendent Julia Pendry, who is in charge of security for the high-profile event, today insisted that officials are prepared for any eventuality.
Getting ready: Workers preparing for Sunday's London Marathon near St James's Park today
Worries: Security has been significantly reinforced for the world-famous event taking place on Sunday
Warning: Visitors to London have been told to make sure they keep their belongings near them
The start of the race will be preceded by a 30-second silence for the Boston victims, and runners have been encouraged to wear black ribbons during the marathon.
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Ms Pendry said today: 'I have increased the number of officers for reassurance patrols by several hundred. It's about making sure that people who come to London on Sunday feel safe when they are in the city.
Mourning: London Marathon runners will wear black ribbons like this one during Sunday's race
'It is a good 40 per cent increase on last year on numbers of officers on the ground. We've got more search dogs out, we have got more on high visibility patrols.'
The Metropolitan Police has been in close contact with the FBI and Boston Police, but says there is no reason to fear a copycat attack on Sunday.
'We're in touch with the Americans all the time,' Ms Pendry added. 'At this time there is no link whatsoever between the Boston Marathon atrocities and the London Marathon on Sunday.
'What we have got is a number of contingencies. I have several contingencies should anything change between now and Sunday - we can then react to anything that should happen.'
Visitors to the capital have been warned that they must keep their belongings on their person at all times to avoid security scares.
'Of course bring your bags, but please keep them with you,' Ms Pendry said.
Virgin London Marathon has pledged to donate £2 for every finisher to The One Fund Boston set up to raise money for victims of the explosions.
Attack: The aftermath of the Boston Marathon bombing on Monday which left three dead and 170 injured
Undeterred: Mo Farah has not changed his plans to run half the course in his home city
Around 35,500 people are expected to cross the finish line on The Mall, meaning at least £70,000 is likely to be raised.
Paralympic athlete Tatyana McFadden, who won the women's wheelchair title in Boston on Monday two hours before the deadly bomb blasts, has said that she will compete on behalf of the American city.
'I'll be racing for the people of Boston,' she said. 'On Sunday we will all have what happened there in the back of our minds.'
Event: The marathon pictured passing through Trafalgar Square last year; there will be 40 per cent more police officers on duty on Sunday
Double Olympic champion Mo Farah, who comes from London, will be running half the course, and insisted he never considered pulling out of the event.
'All my support goes to the people in Boston,' he said. 'But this is home for me so I've got to feel comfortable. For me, this is the place to be.'
The medals ceremony will be hosted by Prince Harry, who elected not to cancel the long-standing engagement in the wake of the Boston atrocity.