London Marathon: Mo Farah and Mary Keitany eye records in 'hottest ever' race

Sunday's 38th edition of the London Marathon is expected to be the hottest ever run, with temperatures predicted to reach 23C.

The previous warmest races in the capital were in 1996 and 2007, when the highs of 22.2C were recorded.

Organisers have added extra water supplies for Sunday and will deploy six run-through showers to cool runners.

"We have numerous contingencies. Listen to your body, change your race plan," said race director Hugh Brasher.

Around 40,000 runners from around the world will take part, but organisers have urged them downgrade their finishing-time expectations in light of the conditions.

"That's the first piece of advice we are giving runners - don't think of this as being a personal-best course if it is going to be that warm," said event chief executive Nick Bitel.

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Runners are also advised to wear sunscreen and consider whether any fancy dress could be dangerous.

A record 386,050 people applied to run this year's race, including 58,534 from outside the United Kingdom.

Farah's return to marathon

Four-time Olympic champion Mo Farah will draw the biggest cheers in the men's elite field.

The 35-year-old finished eighth in the 2014 race and has now returned to road running full-time after hanging up his spikes last year.

Welshman Steve Jones - whose 33-year-old British record survived Farah's 2014 attempt by more than a minute - told BBC Sport he expected Farah to this time "smash and obliterate" his mark of two hours seven minutes 13 seconds.

Farah agrees he should be stronger than four years ago.

"I've definitely prepared differently this year compared to 2014. When I ran the marathon in 2014 I had to think about saving energy for the track but this year I've gone hard at it," he said.

Farah ran half of the 2013 marathon before dropping out, as arranged, to get a feel for the course before his marathon debut in 2014

"It's a great feeling not to have the same pressure as I do on the track. I'm just going to stick to my plan."

Farah is up against a packed field with Kenya's Olympic champion Eliud Kipchoge returning to the capital for the first time since winning the race in 2015 and 2016.

Kipchoge, 33, fell 26 seconds short of breaking the two-hour barrier last year as part of a sportswear-sponsored stunt which fell outside world-record conditions.

Also in the field are Kenyan defending champion Daniel Wanjiru and Ethiopia's Kenenisa Bekele, who has set the second fastest official time over 26.2 miles of 2:03:03.

Keitany takes aim at Radcliffe mark

Keitany has won the New York and London marathons three times apiece as well as completing a similar Great North Run hat-trick in September

Whether Kenya's Mary Keitany intends to moderate her own expectations in the heat is not clear.

The 36-year-old defending champion is running with male pacemakers in an attempt to overhaul Paula Radcliffe's women's record of 2:15.25, which she set in the 2003 race.

Keitany, who is also aiming to match Ingrid Kristiansen's record of four victories in London, was more than a minute ahead of the pace required at the halfway point of last year's race, but could not maintain her speed alone in the second 13.1 miles.

"Running 2:15 is not easy, it is something else," Keitany told the Guardian.

"We are trying to follow in the footsteps of a legend, Paula. But because the London Marathon have decided to put in male pacemakers we have to try to see whether it is possible. We will try our level best to see if we can go under."

Weir aims for magic eight haul

David Weir and Marcel Hug will renew their rivalry in the men's wheelchair race

Six-time Paralympic gold medallist David Weir is back to defend his wheelchair title after collecting a record seventh victory in the race 12 months ago.

Swiss rival Marcel Hug, who finished just a second behind the 38-year-old Briton last year, is in a field that also includes Australian Kurt Fearnley just a week after his victory in the Commonwealth Games marathon on the Gold Coast.

In the women's race, Manuela Schar aims to follow up on her 2017 victory in which she set a new course record. The Swiss has already landed one major marathon title in 2018 with a win in Tokyo.

American Tatyana McFadden, who won four London Marathon titles in a row between 2013 and 2016 but missed last year's race with blood clots, is likely to be Schar's chief threat.

£890m raised and rising

However, the majority of the 800,000 spectators turn out to see ordinary people taking on the distance.

Three quarters of competitors run for a charity and in 2017 £61.5m was raised for charitable causes. Since the marathon's inauguration in 1981 it is estimated that more than £890m has been raised in total.

Among those taking part this year are a team of 18 firefighters who attended June's Grenfell Tower fire, in which 71 people died.

The group, which consists of firefighters from stations in North Kensington and Paddington, are raising money to support residents and colleagues affected by the tragedy.

Also running is a 10-strong team from the Stephen Lawrence Charitable Trust, marking 25 years since the teenager, who took part in the 1988 Mini Marathon, was murdered in a racist attack in Eltham.