London Marathon 2016: Stellar fields, world record hopes and a giant dinosaur

Sunday sees the 36th running of the London marathon.

And judging by the look of the fields for both the men's and women's races, it could be the finest battle for years as all of the world's best marathon runners have confirmed participation at one of the greatest events on the athletics calendar.

Defending London Marathon champion Eliud Kipchoge of Kenya will renew his rivalry with 2014 winner and compatriot Wilson Kipsang.

Kipchoge, who currently leads the world rankings, clinched victory over 33-year-old Kipsang at last year's London Marathon by just five seconds.

And that win was far from a one-off: he has won five of his last six major city marathons, including the 2015 Berlin Marathon, where he clocked a personal best of two hours and four minutes - just 63 seconds off the world record, which is held by Dennis Kimetto with 2:02:57 set in Berlin in 2014.

Kimetto, another Kenyan, is also taking part on Sunday, as is another Kenyan Stanley Biwott (personal best: 2:04:55) as well as Ethiopian quartet Endeshaw Negesse (2:04:52), Kenenisa Bekele (2:05:04), Tilahun Regassa (2:05:27) and Abera Kuma (2:05:56).

Oh yes: there's also Eritrea's Ghirmay Ghebreslassie, who became the marathon's youngest-ever world marathon champion by winning in Berlin last summer at age 19. His level of attainment at such a young age is unheard of in long-distance running, and it's impossible to guess just how fast he might one day run.

"I will work hard to defend my title in London and, together with Wilson, Dennis, Stanley and those from other countries, make it a fast and wonderful race," said Kipchoge. They are unlikely to disappoint.

World records have been broken in London before now, but it's unlikely that they will be this year. In an Olympic season the best of the best will be working with an eye to peaking in Rio - where a gold medal will earn them no money, but years of enhanced appearance fees that will comfortably outweigh any world record bonuses on offer.

Furthermore, it's a long time since a marathon world record was broken on the streets of the English capital. Khalid Khannouchi did so back in 2002 in the men's race, and Paula Radcliffe set her women's world record (of 2:15:25) in London a year later.

The simple fact is that while London is a fast course, Berlin is a faster one: every world record set in the discipline for the last 13 years has been set in the German race, and the course record of 2:04:29 (set by Kipsang in 2014) is over a second and a half slower than the record.

Yet balance all that against the big reason to suggest that there could be a surprise on the cards: only three athletes from each country will be able to take part in the Olympics, and the selection process means that they'll go to the runners with the fastest times. Simply put, none of these runners can afford for London 2016 to be a slow race if they are to make certain of their berth in Rio.

The women's field for the race this year is just as strong, if not stronger, than in the men's race. Defending champion Tigist Tufa of Ethiopia and marathon superstar Mary Keitany of Kenya are both taking part.

Keitany has an incredible record of winning her races, with an almost-ridiculous 75% success rate in recent years. She's also the second fastest female marathon runner of all time behind Radcliffe, having set her personal best of 2:18.37 at the London marathon in 2012 (though she went on to finish fourth in the Olympic marathon in the same city later that year).

She's not cracked the 2:20 mark since then, however. And the competition is fierce with several other sub-2:20 runners in the field: last year's Berlin marathon winner Gladys Cherono of Kenya (with a personal best of 2:19:25), 2015 Chicago champion Florence Kiplagat of Kenya (2:19:44), and Ethopian duo Aselefech Mergia (2:19:31) and Mare Dibaba (2:19:52, the reigning world champion) are also in the race.

As for a world record? As you see from the times above, no woman has run within three minutes of Radcliffe's stunning time from 2003; it's nigh-on impossible to imagine such a huge leap in performance from any of the field.

As ever in London, dozens of finely-honed runners who've spent years working on their speed and stamina will throw all their training out of the window by taking part in the race while wearing absurd costumes.

We'll be looking out in particular for Lee Small, James Lafferty, Michael Palmer and Stevie Clifford-Tucker, a quartet of firefighters from the suburbs of north London who'll be running together in a giant fire engine.

There are also people running in chain mail, and a mum from Reading who looks likely to earn herself plenty of fans - and even more money for the Action on Hearing charity - by taking on the 26.2 miles in a rather fetching Snow White costume.

But the man who has earned our greatest pre-race admiration is Ian Bates, who is raising money for St Catherine's Hospice in Crawley by donning a frankly enormous dinosaur costume that stands over 7ft tall, is a good 10ft long and apparently weighs over 20kh. How can you not love that?