Part 1

Gabby Logan presents live coverage of the 36th London Marathon as world-class runners and 38,000 fundraisers compete in one of the world's most famous races.

There's a rematch in the elite men's race between last year's top five finishers, including the two most recent champions. Eliud Kipchoge beat two-time winner Wilson Kipsang last year in a thrilling sprint finish, with world record holder and fellow Kenyan Dennis Kimetto in third.

The expected challengers include three-time Olympic track gold medallist Kenenisa Bekele and world champion Ghirmay Ghebreslassie of Eritrea.

Ethiopian Tigist Tufa defends her title against five athletes who have run sub-2:20 marathons, including compatriots Mare Dibaba, the reigning world champion, and 2010 London winner Aselefech Mergia, as well as Kenya's two-time victor Mary Keitany.

British Olympic places are up for grabs, with the first two finishers guaranteed a trip to Rio provided they have the qualification time.

Hometown favourite David Weir bids for a record seventh win in the men's wheelchair race, having lost out last year to American Joshua George, who defends his title.
In the women's wheelchair race, Tatyana McFadden of the USA seeks a fourth straight London crown, having set a course record in each of the last three years.

As well as the elite races, we will hear from amateur athletes who are running for charities which benefit from one of the iconic events in the British sporting calendar.

Reporting along the 26.2 mile route will be Colin Jackson, Denise Lewis, Ore Oduba and Radzi Chinyanganya, with commentary by Steve Cram, Brendan Foster, Rob Walker, six-time London Marathon wheelchair race winner Baroness Tanni Grey-Thompson and Paula Radcliffe.