The London Marathon takes place on Sunday 23rd April. Coverage of this year's race begins on BBC1 at 08:30.
Women's Race Preview - 09:15 Start
The women's race is the strongest field ever assembled for a marathon and is hard to predict; a realistic case can be made for all eight athletes who have personal bests sub-2:22.
Now 35 years old, Mary Keitany had started to look past her best in recent years, falling last year in London and finishing ninth. She confounded that view when winning in New York in November, though, in a fast time, and has broken her best time for the half-marathon when winning in the UAE in February this year in 65:13. Only Paula Radcliffe has run faster than Keitany in London and this could be her swansong.
Track-legend Tirunesh Dibaba ran an impressive 2:20:35 on her marathon debut in London in 2014 to finish third (she may have won that year if not dropping a drinks bottle at an aid station) and showed she retained her best form on the track when returning in the 10,000m in Rio last summer after a career break to give birth to her son. She has been running adequately in half-marathons since then and will be feared if in contention in the closing stages.
Tigest Tufa has a fantastic record in London - a first and a second in two outings - but neither of her runs were especially quick and it is likely she will have to run at least two minutes quicker to win here. Nonetheless, she joins a list of possible winners who include Berlin-specialist Aberu Kebede, perennial London podium-finisher Florence Kiplagat, and major-championship specialist Mare Dibaba.
The most interesting challenger to Keitany and Dibaba, though, is likely to be marathon debutant Vivian Cheruiyot. She comes closest to rivalling Tirunesh Dibaba for track form and beat her Ethiopian rival when winning the Great North Run in November last year, her debut on the roads at the half-marathon. Cheruiyot ran a solid half-marathon in Lisbon last month and, if she has her preparations right for her inauguration at the full marathon, then she will be hard to beat.
Verdict: Too close to call, with Keitany, Tirunesh Dibaba and debutant Cheruiyot the most likely winners
Men's Race Preview - 10:00 Start
If Kenenisa Bekele is fit, then this should be a one-man attempt on a world record. Although organisers will try and suggest the race contains its usual stellar field - with six runners having sub 2:06 personal bests - there are so many doubts and questions about all-but Bekele that their marketing attempts will be unconvincing.
Arguably the greatest track distance runner of all time, Bekele made an indifferent transition to the roads: although winning his debut in Paris in the sixth-fastest induction in history, that was followed by three disappointing appearances, culminating in a third in London last year that saw him left out of the Ethiopian team for Rio 2016. Bekele instead targeted the Berlin marathon in September, winning in the second-fastest marathon time in history, only six seconds adrift of the world record. He was reportedly only half-fit for London last year - coming here on the back of eight weeks training - and despite pulling out of the Dubai Marathon in January after a trip at the start and complaining of sore calves at half-way, he is fantastic value at any price around 2.001/1.
Bekele's task will be made much easier by the absence of Stanley Biwott, who pulled out of race with a fortnight to go citing a recurrent hamstring problem. For many, then, Bekele's main rival will be his compatriot, Tesfaye Abera, who won his marathon debut in Mumbai in 2015, and has since gone on to win four more, including a near course-record 2:04:24 in Dubai in January 2016. Abera's form is inconsistent, though. He dropped out of the Rio marathon because of the heat and was only 5th in a slow 64:53 in a half-marathon in January. It can be unwise to read too much in to preparation races - athletes often remain in heavy training making it difficult for them to run at their best - but nonetheless Abera has a bit to prove.
Likewise, the others. Feyisa Lilesa has not reached the potential he showed as a 19-year-old breaking 2:06 on his debut. Now relocated to the US, expect to see his future targeting the major championships and the US-based Marathon Majors. Abel Kirui has never run well in London - fifth is his best result - and his personal best was run eight years ago in Rotterdam. He only merits consideration because of a surprise return to form in Chicago in October, but that was the slowest winning time in Chicago for nearly 20 years and expect him to be out of contention early at the pace London will be run at.
Most likely to trouble Bekele may be Daniel Wanjiru. Unrelated to Sammy (see below), Daniel is still green and won in an impressive 2:05:21 in Amsterdam last year, but he ran a dreadful half-marathon in the UAE in February and can't be recommended with any confidence.
For those looking for an outsider, then, the best option may be debutant Bedan Karoki. An ever-present at the front-end of track 10,000m races in recent years and second in the world half-marathon championships, Karoki has run six of his seven half-marathons to date in under 60 minutes and is the most talented athlete on show here aside from Bekele. An each-way interest at around 12.0011/1 would likely see a return and give hope should Bekele underperform.
Verdict: Back Kenenisa Bekele to break the world record and have an each-way interest in debutant Bedan Karoki
The course is flat - actually, it's very slightly downhill overall - making it a rival for Berlin among the Marathon Majors as the fastest course in the world. Last year's London winner, Eliud Kipchoge, ran a course record 2:03:05 and probably could have broken the world record (he was only eight seconds' shy of it) had he been more aware of the possibility.
The start in Greenwich will be fast, with pacemakers leading the way. Even though the pacemakers are internationally able runners - and these rabbits will occasionally carry on setting the pace to record a surprise win - it is unlikely to happen in London. If they last beyond 30km, they've done well.
By the time the field reaches Cutty Sark, just before mile seven, it is likely the lead group will have been whittled down to just a few runners. If your fancy isn't in that group, they won't win. Given that only a small handful of either field have a realistic chance of winning, most of the other competitors will be sticking to their own pacing strategies, which will see them adrift of the leaders. This will include all the European representatives.
Crossing Tower Bridge, just before the half-way point, we'll know if a world-record is on the cards in the men's race. Last year, Kipchoge's group went through at 1:01:24 (at that time the fastest half-way split in marathon history). Bekele, who went through half-way in 1:01:11 in Berlin, will need to be on a similar schedule if the record is to fall on Sunday.
Incidentally, if travelling to London for Sunday, the half-way point is the best place to watch the London Marathon: somewhere between Tower Gateway and Shadwell on The Highway will give you a quiet-ish opportunity to see all the runners twice, with plenty of refreshment options nearby.
Docklands, between miles 15 and 20, can often be the key to the race. A mid-race move can often break less buccaneering competitors. When Sammy Wanjiru won here in 2009, he ran Mile 19 in 4:19, destroying anyone else with pretensions of winning. Be prepared to back those making a play for race victory in the psychologically most-difficult part of the race.
The final stages - running down the Embankment towards Big Ben, passing the Houses of Parliament and turning into The Mall - have seen plenty of close finishes over the years. Don't overthink your bets, though. The various factors that commentators will assess to build the tension - historic track speed, who has led the most, who is most experienced - are largely irrelevant. All athletes will be near their limits. Back the one who looks like they are in the least pain, which will probably be none of them.