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David Weir and Brigid Kosgei will be at the start line, as the London Marathon returns back to London's streets.
Virgin Money London Marathon Date: Sunday 3 October Time: 08.00 BST (elite wheelchair race), 09.00 (elite women and mass start), Course: Blackheath and The Mall BBC coverage. Live coverage on BBC Two and BBC One starting at 10:00. Uninterrupted coverage with extra streams on Red Button and online. Live text available from 08:00
On Sunday, the London Marathon will return to London's streets for its first major staging in over two years.
Over 40,000 runners will be joining some of the best around the course, which starts in Blackheath but finishes 26.2 miles later under Buckingham Palace.
The group will be joined by another similar number who will complete the distance "virtually" via an app that tracks their progress on a course they choose.
The race was moved from its usual April date to accommodate the coronavirus pandemic that forced the suspension of all sporting events around the world.
A small elite field raced 19 laps around St James's Park last October. The mass portion of the event was held remotely.
Hugh Brasher, London's race director, said that this year's event, 40 years after the original race in 1981, "could easily have been the most memorable ever".
He said, "It will bring you joy and true emotion." It is much more than a marathon. It's about bringing people together, and that is what we have been missing so much over the past 18 months."
This is everything you need to know regarding Sunday's race.
Records, revenge, and breakfast buffets
In 2020, Brigid Kosgei of Kenya was victorious over the rest.
After a string of wins in 2019, and 2020, Brigid Kosgei, Kenya's world record holder, is hoping for a third consecutive victory in this race. Katrin Dorre of Germany was the last female athlete to achieve a treble in women's racing with wins in 1992 and 1994.
She will be up against Lonah Salpeter of Israel, who is seventh fastest over the distance. Joyciline Jepkosgei, Kenya's reigning New York City Marathon champion, will also be challenging her for a win in London.
Kosgei insists that she is ready for the challenge, just eight weeks after earning Olympic silver in hot and humid conditions in Sapporo (Japan)
She said that she felt well after a week.
"I like too much London. That is the main reason. London is my favorite city. The course is my favorite. They are so welcoming. Even race organizers. The place is great and the people who cheer us on along the way are a pleasure to be in."
Natasha Cockram and Charlotte Purdue, the first Britons in the 2019 and 2020 races, aim to qualify for next years' World Championships in Oregon.
Purdue, fourth fastest woman in Britain, was disappointed not to be selected for the Tokyo Olympics. She felt she had been unfairly overlooked because of her medical condition.
She told BBC Sport that she was angry and annoyed but once London became my focus, I channelled all of my energy towards London."
"Now, I'm all in for this race on Sunday."
Shura Kitata, an Ethiopian man of color, explained that he had eaten a lot to fuel his surprise win over Eliud Kipchoge in last year's men’s race.
We are hoping that the hotel of elite athletes has stockpiled pastries, because Kitata will be back to defend his crown.
Kitata stated, "Last year’s win was very significant because Eliud has such a strong, famous runner."
"It has given me strength in my psychological preparation and also attracted a lot attention from the general public."
Kipchoge, who won four of the five previous London Marathons before 2020 is not present. Britain's Mo Farah is also absent after failing to qualify for Tokyo 2020 and having suffered a stress fracture in his foot.
Birhanu Legese of Ethiopia, who is the third fastest man over the distance, and compatriot, world silver medallist Mosinet Gemew, are in the field.
David Weir, eight-time winner of the men's wheelchair in Great Britain, competes in his 22nd London Marathon. However, he will be up against Marcel Hug from Switzerland, who won four golds at Tokyo 2020.
Along with Brent Lakatos, Canada's defending champion, Daniel Romanchuk from the USA is in the field.
Considerations for covid remain
The 2020 race was held away from crowds
There are still precautions for the race, with more than 240,000 positive Covid test results across the United Kingdom in the seven days prior to race week.
Before they can line up in London, all runners must pass a negative lateral flow testing. Runners are encouraged to bring one person to support and observe them.
If large groups gather at any point, stewards will ask them to move along the route.
The race will begin with smaller runners being released in the first 90 minutes. To reduce transmission, the baggage system which normally takes warm-up kits from the start to finish has been simplified.
Organisers stress that fuel shortages should not be a problem and encourage runners to use public transport to get to and from the start and return.
Brasher stated, "Those services have been best for people to reach the event in its historical and will continue to be that way."
Forward thinking and back of the pack care
How the London Marathon achieves sustainability
The race will feature electric lead vehicles at the front, compostable cups and goodie bags made from sugarcane at the finish line.
The London Marathon introduced several measures to reduce the amount of carbon and waste produced by the race.
With 84,125 applications from overseas to participate in the 2020 race, the race has been a huge draw for runners around the globe.
To offset the international runners' travels to the starting line, organizers have created a carbon tax. They also funded tree-planting projects for Kenya and east London that absorb carbon dioxide.
After some of the slowest runners in 2019 reported being insulted and then finding that the clean-up was taking place before them, there have been improvements to the running experience for those at the back.
2019: Liz Ayres, Pacer, tells Victoria Derbyshire program that contractors called slower runners "fat" or "slow".
A 50-strong team will be able to walk the course with a DJ, accompanied by an eight-hour-long pace. Additional officials will be available at every 400m starting at 16 miles to assist runners who are having difficulty finishing the course.