Nairobi, Jan 15 (IANS): Top Kenyan marathoners have termed April's London Marathon among the toughest races ever staged as organisers rolled out one of the most imposing fields of all-time.

Led by world record holder and 2012 champion, Wilson Kipsang, the assembled cast in the men's race will feature three athletes who have dipped under 2:04 -- all Kenyans -- as they face British Olympics and worlds double champion, Mo Farah, who will debut at the distance, reports Xinhua.

Kipsang has gone under the barrier twice in his career, 2:03:42 he posted at the 2011 Frankfurt race before he smashed the world record last fall in Berlin by running 2:03:24.

The 2011 winner and course record holder, Emmanuel Mutai, clocked 2:03:52, the fastest ever losing time in marathon history when he finished second in Chicago last October.

Two-time New York winner, Geoffrey Mutai, ran 2:03:02 at the 2011 Boston marathon although the course is not eligible for world record considerations.

"That race will be very hot and for us, it presents a challenge to get into good shape. My prayer is my body will be in good form so that I can run to the best of my ability," Geoffrey said Tuesday upon receiving the news that the elite men's line-up had been released.

Speaking from his training base, Geoffrey added: "I'm yet to get into my competition shape so I'm working hard to get there."

He finished second over 12km at the Kenya Police Cross Country Championships on Saturday in Nairobi.

The 2:04:40 course-record holder Emmanuel, who has come second at the same event on two occasions, 2010 and last year, said he was not sure he would return as he embarked on getting to shape.

"I will have a better idea of my prospects in the coming weeks when it all becomes clear in training but for now, I have just started. I welcome every return to London since it is a race that means a lot to me," he explained.

Having won the Fukuoka Marathon Dec 1 on his second attempt, the 2007 worlds 10,000m bronze winner, Martin Mathathi, is relishing his World Marathon Majors debut.

"I'm excited to be in the race and I will try my best. My intention is to train well for the race and everything is possible from there. It would be great to win the race where my friend (the late) Samuel Wanjiru did so well but it will take a lot. Running the marathon requires adequate preparations," Mathathi, who ran 2:07:16 in Fukuoka, said from Eldoret where he has shifted his training base.

The Nyahururu-born athlete will feature in the Marugame Half Marathon in Japan at the end of the month before returning to step up his preparations for London.

Wanjiru, the 2008 Olympics and 2009 London champion in the previous 2:05:10 route best, also hails from the same town.

The African challenge in one of the biggest marathons on the planet also features reigning Olympics and World champion Stephen Kiprotich of Uganda.

Defending champion Tsegay Kebede of Ethiopia leads countrymen Ayele Abshero (2:04:23/2012 Dubai champion), Feyisa Lilesa (2:04:32/2011 world bronze medallist) and an exciting debut for Ibrahim Jeilan, the 2011 World 10,000m gold medallist to the race.

All attention will be on the headline act, England's Mo Farah who ran the first half of the race last year to assess the course and opposition in preparation for his full marathon debut.

He went on to win the World Championships 10,000m title in Moscow last August before retaining his world 5000m crown, adding another global track double to his twin Olympic triumphs from London 2012.