To anyone who knows anyone killed or injured in the Boston Marathon explosions, the headline may seem harsh, but I really believe it.

The last stretch tends to be the most emotional. In 2003 BBC commentator Brendan Foster had texted me to say the cameras were going to pick me out on the last half mile of the London marathon – yes, I run with a phone – so I forced myself to shed a few tears a mile or two short of that. Like many marathon runners, I was doing it for a cause, Leukaemia and Lymphoma Research, and in memory of a person, my best friend John Merritt.

In addition to all the emotion wrapped up in all the causes and memories being supported and recalled, marathon runners have all had to train for hours and hours, often alone. Most have endured moments of pain en route. Many have hit the wall, felt they could go on no longer, but somehow found the strength and resilience needed to keep going. And by the end the crowds are sharing in the sense of exuberance and achievement. So that last stretch of road is a very exciting, unified, happy place to be. Which makes it a very good place to disrupt with the view to terrorising the runners, the crowds and most of all the wider public and politicians. 

Before the 2003 London marathon, I was fully briefed on the security operation, because it came with Iraq as the dominant issue of the time. One or two people suggested I pull out. But the Met assured me they had everything under control. I ran with one of Tony Blair’s protection officers, but left him after a few miles, feeling the thrill of beating a fit copper was greater than any concern about security! You do think of things like terrorism when running, at least I did,  and you are conscious of what an attractive target these mass participation events would make. But there is something even more powerful than a bomb in a huge crowd of runners, and that is the power of the human spirit.

Terrorism, whether we like it or not, does make us think and act differently. I am writing this at Heathrow, where the security measures are a direct response first to Irish and now Al-Qaeda and other global terrorist organisations  There will be runners entered for the London marathon on Sunday perhaps having second thoughts. They shouldn’t. Those who do run will doubtless, amid the myriad weird and wonderful thoughts that flood into the mind as the 26.2 miles are ground out step by step, have the odd ‘what if?’ ponder about a bomb lurking nearby. All of which will add to the emotion at the end this time. None of which should stop them taking part, assured it will be one of the greatest feelings of their lives when they cross that finishing line.