Paula Radcliffe
Former women's marathon world record holder on BBC TV

Sifan Hassan looks confused. This is not a niggle that she knows how to handle, this is something new and she doesn't know what to do to help ease it off.

She looks a little more comfortable than she did before, so maybe it was a bit of cramp.

She was stopping to do a few stretches but she didn't seem to know which one would work. But considering those stoppages, she is still in a decent position and she is such a competitive racer that she will not want to stop.

It's going to take someone telling her to stop for her to do that.

Steve Cram
Marathon commentator on BBC TV

These are worrying signs for Sifan Hassan. She is holding her side, and grimacing. It's not just generic marathon hurting, because it's too early for that.

She doesn't want to hurt herself and write off her track season here. It wouldn't be wise to keep charging through this marathon if that is an injury.

We've talked about Sifan Hassan in the women's race and she seems to be struggling. She's fiddling with her left hip as she hangs onto the back of this lead group...

Now the grimaces get worse and Hassen stops twice on the road to stretch out that left leg.

She's carrying on... for now.

One thing has played a big part in the preparation for many of the today's runners - Ramadan.

The holy month of fasting in Islam involves abstaining from eating or drinking during daylight hours so how does that fit in with everything needed to prepare yourself for running 26.2 miles?

Haroon Mota has been telling BBC Sport how he has been making himself eat a big meal at 4am for the past month to help him through.

"Fuelling and hydrating during the month of Ramadan if you are training isn't easy, I'll be honest," he told BBC Sport.

"Trying to put food and drink down your mouth at 4am, you probably don't feel hungry but you know that you have to eat. I have to give great priority to my hydration the moment that the sun goes down, so while it's tempting to jump straight to the sweet treats and the fried samosas, I have to take that in moderation."

Read more here

Image source, Getty Images

Dutch runner Sifan Hassan is primarily a track runner. She won the 5,000m-10,000m double at the last Olympics in Tokyo.

Today is her first race over the marathon distance and currently she's at the back of that lead group.

"I'm actually in better shape for 5,000m and 10,000m right now but I don't know about the marathon," she said.

"Right now I'm just thinking I really enjoyed it here but I have a really good feeling about the track.

"I don't have any time in my mind, my goal is to just meet the marathon. I want to learn."

Steve Cram
Marathon commentator on BBC TV

We are talking about Sifan Hassan quite a bit because we are not sure how long she is going to be able to keep up with the lead group, because she doesn't run this distance normally.

She is dropping back gradually and has been careful at the drinks' station too, which is another thing she will not be used to [because this is the track athlete's marathon debut].

That's a skill in itself. She looks like she has had her water a little bit too quickly, and when you are breathing that heavily it can easily go down the wrong way and make you sick.

It is really fascinating to watch how she is handling all the different elements of the marathon.

Baroness Tanni Grey-Thompson
Six-time London Marathon wheelchair champion on BBC TV

Marcel Hug is a long way clear now and his hand speed has dropped a bit, but he looks very comfortable.

There is a group of four in the women's race that have been sharing the lead pretty evenly so far so it's way too close to call at the moment.

Paula Radcliffe
Former women's marathon world record holder on BBC TV

Sifan Hassan has drifted back a little bit, sheltering from the lead group rather than running with a clear road ahead.

But it's Genzebe Dibaba who is pushing out in front now and urging the pacemakers to pick it up.

They went through 10km in 32:37. They are looking good for a 2 hour 17 minute finish.

Marcel Hug now has a two-minute lead at the front of the men's wheelchair race. They're beyond halfway now and Hug could be eying his own course record. This has been impressive stuff.

There's a group of four in the lead of the women's race. Defending champion Catherine Debrunner is there but it is her fellow Swiss Manuela Schar who is in first place as it stands.

There's a group out in front of the women's elite race, which includes all of the main contenders.

The pace is decent. It's not quite course record standard just yet but not far off.

Paula Radcliffe
Former women's marathon world record holder on BBC TV

Mo Farah looks relaxed. The feeling you get on the start line is incredible, it gets your heart going just that little bit more.

The instinct is to go fast when you have that buzz and he has done that, he is in a good position.

He wants to give himself the chance for one last tough run on the streets of London and he says he is in good shape, so it will be interesting to see if he can stay in that lead group.

Mo Farah gets a huge cheer on the start line before Eluid Kipchoge gets the race under way.

The star names sprint down the road before thousands others follow behind.

Good luck, everyone.

Steve Cram
Marathon commentator on BBC TV

Many would say it is the world's greatest marathon and we have some of the greatest distance runners of all time taking part.

Amos Kipruto is the defending champion and Kenenisa Bekele has the second-fastest marathon time of all time.

Mo Farah needs no introduction, he is on the line for the last time.

We've talked about how good the women's field is today and the men's is right up there too.

Four of the fastest five men in history are taking part.

They're up on the start line. The masses will follow behind them.

Image source, Getty Images

London Marathon race director Hugh Brasher urged the crowds to get behind Mo Farah as the British running legend says goodbye to the race.

Speaking on Wednesday, Brasher said: "I hope the crowd are cheering him on every step of the way to thank him for all he has done."

He added: "My only expectation is I really hope he runs with a smile on his face."

Catherine Debrunner set a new course record at last year's London Marathon.

She is in contention again today.

Marathon world record holder Eliud Kipchoge, who is the official starter for today's men's race, on BBC One: "I love being in London. The crowd is always wonderful and it's great to see how the running community is coming together.

"London is like home to me and it is the place to be for a marathon.

"It is a very strong field [in the men's elite race]. I don't know if my time will be beaten today but records are made to be broken so you never know!

"I have known Mo Farah for a long time and I wish him all the best in his last race. He is an inspiring man."