Records under threat in London Marathon
(L-R) Ethiopia's Tsegaye Mekonnen, Kenya's Emmanuel Mutain, Uganda's Stephen Kiprotich, Kenya's Geoffrey Mutai, Ethiopia's Tsegaye Kebede, and Ethiopia's Ibrahiim Jeilan pose for photographers near Tower Bridge in London on April 9, 2014 - by Carl Court
Farah, the reigning Olympic and world 5,000 metres and 10,000m champion, was to take his place in an elite men's field due off at 10:00am 0900 GMT).
Among his competitors will be Kenya's Wilson Kipsang, who set the world marathon record of two hours three minutes 23 seconds at September's Berlin Marathon.
Also included are Emmanuel Mutai, who set the London course record of 2:04:40 in winning three years ago, and Geoffrey Mutai, twice winner in New York.
Uganda's world and Olympic champion Stephen Kiprotich is also set to be on the start line as will Ethiopia's double London champion Tsegaye Kebede and compatriot Haile Gebrselassie, who, at the age of 40, will seek to take the field through to the three-quarters mark in world record pace.
The elite women's race, which set off ahead of the men, featured a high-class field, who will have the world record for a female-only marathon of 2:17:42 set by Britain's Paula Radcliffe in London in 2005 in their sights.
Ethiopia's Olympic and world 10,000m champion Tirunesh Dibaba, like Farah, is making her marathon debut.
She was joined on the start line Sunday by 2013 London winner Priscah Jeptoo of Kenya as well as Ethiopia's reigning Olympic marathon champion Tiki Gelana, whose hopes of victory in London last year were dashed by a collision with a wheelchair racer.
This year the wheelchair racers were first on the course with Britain's Paralympic champion David Weir looking to become the most successful racer in the event's history by winning his seventh London title.