Amid the tightened security and heightened emotion prompted by the tragic events in Boston last week, Tsegaye Kebede of Ethiopia and Kenya's Priscah Jeptoo produced powerful runs over the closing stages to win the men's and women's titles in today's Virgin sponsored London marathon.

In conditions that were close to good for the competitors and perfect for what were estimated to be larger than normal crowds along the route, Kebede came from behind to pass Emmanuel Mutai of Kenya, who had looked set for victory when he led by 28 seconds with just over two kilometres to run.

Mutai faded badly, though, and could do nothing as 26 year-old Kebede, who also won here in 2010, glided past him into the lead. The Ethiopian, who won bronze at the Beijing Olympics but missed out on selection for the Games here last year, looked supremely comfortable as he crossed the finish line, 29 seconds ahead of his rival who initially needed assistance at the race’s end.

With a hugely impressive field assembled for the men's event, much of the race had been run at close to world record pace but as the then leading group of Mutai, Ayele Abshero, Feyisha Lilesa and Stanley Biwott started to size each other up and things began to become more tactical around the 30 kilometre mark the pace slowed significantly and Kebede's winning time was ultimately a minute and 44 seconds off the course record set by Mutai two years ago.

“I had a little pain in my side during the early part of the race,” he said later, “but as time went on it got better and better. I could feel myself getting closer and closer to Mutai and that made me stronger. It was a great day to run a London marathon and even better to win.”

Mutai was predictably upset at not having been able to drive home his advantage. “I’m very disappointed,” he said. “I thought I might win today but I had some trouble with my hip and I couldn’t pick up the pace in the closing stages.”

Jeptoo, meanwhile, broke all of her rivals over the second half of a race she gradually came to dominate. The 28 year-old, whose training partner Rita Jeptoo won in Boston last Monday, was still involved in something of a duel with compatriot Edna Kiplagat at the 30 kilometre mark, but the eventual winner passed and then started to pull away from her rival soon afterwards and the result was never in doubt through the closing stages, with the Olympic silver medallist, a former winner in Paris, Turin and Porto, powering home to complete the biggest win of her career with a minute and 17 seconds to spare in a time of 2:20:15.

“I knew this morning that I was going to run well,” she said afterwards, “but there was such a strong field that you were always worried that someone would do better. It wasn’t until about 25 miles that I got that confidence back and felt that I would win.”

Rather less happy was Olympic champion Tiki Gelana whose own challenge was effectively ended less than half way through the race when she collided with Canadian wheelchair competitor Josh Cassidy after she pulled across him at a water station.

“It's something I have mentioned before,” said an angry Cassidy who blamed the fact that the organisers time the various elite races so as to have one finish after the other in fairly quick succession.

“I don't know who's responsible, but every year we come to overtake the women, there are 10 chairs going at 20mph and the poor women are scrambling to find their feet. The safest thing would be to have the chairs start first because one of these years a woman is going to have a leg broken, a career ruined. It's just not worth having this programme if the races are going to suffer. It has to change.”

Earlier, the roughly 37,000 starters had observed 30 seconds of silence before setting off in tribute to the victims of the Boston marathon.

The mass participation event was comprised of the usual eclectic mix of runners from around the globe, a great many of whom, including former Republic of Ireland international footballer Kevin Kilbane, were taking part in order to raise funds for a huge range of charities with some € 60 million expected to be raised in total.