World record-holder Wilson Kipsang won the men's London Marathon in a course record two hours, four minutes and 29 seconds on Sunday as Britain's Mo Farah found life tough on his debut over the distance.
Kipsang's smashed the previous London record of 2hr 04min 40sec set by fellow Kenyan Emmanuel Mutai in 2011.
It was a second London victory for Kipsang, the 2012 champion, who outpaced compatriot Stanley Biwatt in the finishing straight.
Tsegaye Kebede of Ethiopia, last year's winner was third, and Ayele Abshero of Ethiopia was fourth.
Kenya celebrated a race double as Edna Kiplagat, runner-up for the past two years in London, won the women's event.
In the men's race Kipsang and Biwott surged away from a leading group of eight after some two-thirds of the way round the 26.2 mile (42.2 kilometre) course.
The two Kenyans were all but inseparable until, with just over a mile left, Kipsang broke his compatriot's resolve with a finishing burst.
- Farah vows marathon return -
"It's really great to win the London Marathon again," said Kipsang.
"It was around 31km that I decided to push harder as I felt very comfortable and strong. I pushed again towards the finish line and that's when I broke away."
Farah, reigning Olympic and world 5,000 and 10,000 metres champion, finished in eighth place having failed to break Steve Jones's British record of 2:07:13, which has stood since 1985.
"I will be back," Farah told the BBC. "I'm not going to finish it like this. I gave it my all but I'm disappointed I didn't go out there and give what the crowd deserve."
British distance great Brendan Foster, commentating on the race, urged Farah to stick to defending his track gold medals at the 2016 Olympic Games in Rio.
However, the 31-year-old Farah refused to be rushed into a decision on his future, saying: "I'm disappointed but you try things and sometimes it doesn't work, but you have to give it a go.
"You learn -- life goes on."
Farah, not helped by missing a drink station shortly after half-way, added: "The field was tough...It was the strongest field ever put together by the London Marathon.
"I've gone straight in at the deep end, but that's what athletics is all about."
The two-times reigning world champion Edna Kiplagat won in 2hr 20:21 with Florence Kiplagat three seconds further back in second place.
After breaking away from the field, the pair remained close together until the final bend when Edna Kiplagat surged ahead.
"I felt very strong so I wasn't too worried," said Edna Kiplagat of the close finish.
Ethiopia's Tirunesh Dibaba, the Olympic and world 10,000 metres champion, marked her marathon debut by finishing in third place.
She had looked set to challenge the Kenyan duo but paid a heavy price for dropping a water bottle and stopping to pick it up. Dibaba finished 14 seconds adrift.
While it was a good day for the women's world champion, it was a tough one for the men's as Uganda's Stephen Kiprotich finished 12th.
Tiki Gelana, the women's Olympic champion, also struggled as she finished ninth a year after colliding with a wheelchair racer in the 2013 London Marathon.
In the men's wheelchair race, David Weir's bid for a record seventh London title saw the Briton just edged out by Switzerland's Marcel Hug, who won in a time of 1hr 32:39.
"This is a really sweet victory and it feels great to finally win this race," said Hug. "It is great to compete against David Weir and also great to beat him."
In the women's wheelchair race, Tatyana McFadden of the United States successfully defended her title just a month after winning a cross-country skiing silver medal at the Winter Paralympics in Sochi.
The 24-year-old won in a course record 1hr 45:11, more than a minute-and-a half clear of Swiss runner-up Manuela Schar.
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