Before a single runner arrives, the route is officially measured by BAF RRC and approved by England Athletics using a calibrated bike that follows the shortest possible line every tangent, every inside curve, every metre counted.
That’s what makes it an accurately measured event, meaning results go on Power of 10 and RunBritain and can count as official PBs.
But here’s the bit most people don’t realise:
No one actually runs the shortest possible line.
It’s almost impossible in a busy race, we all weave, take corners wide etc.
Even before GPS comes into play, that alone adds distance.
On top of that, every certified course includes a Short Course Prevention Factor, an extra 0.1 % built in to make sure the route can never be short.
For a half marathon, that’s around 21 metres extra, so your race is roughly 21.118 km, not 21.0975 km. That’s if you run the perfect lines.
Add in GPS drift (especially around trees or turns), and it’s totally normal for your watch to read 13.2 or 13.3/4 miles.
So next time you see that, don’t panic the course isn’t long.
It’s measured precisely, approved officially, and designed to never be short.
Your watch shows your route; the course shows the standard.
Marcus | Race Director @legacyraces
📸 @whatderricksees behind the scenes
After 36 Marathons, Here’s What I’d Tell Myself Before My First
Is running a marathon worth it?
Only if you respect the distance. The marathon will demand everything from you, physically, mentally, and emotionally. If you’re looking for an easy challenge, this isn’t it. But if you commit, train smart, and embrace the struggle, you’ll learn more about yourself than you ever thought possible.
Knowing all this… would you still run one?
4 truths from my first to my most recent @londonmarathon
1️⃣ 26.2 miles remains relentingly uncomfortable, regardless of how fast you run it. The same facial expressions will apply annually..
2️⃣ Back in the day, I was against short shorts, but here we are… 🫠
3️⃣ Each marathon shows us heightened aspects of ourselves across a range of emotions. Be kind with yourself in how you handle that post race.
4️⃣ Always back yourself, nothing feels better than proving yourself right. 4.55 - 2.58 in my home city!
#livelifetothefullest #ARunnersLife #abbottwmm #TCSLondonMarathon #ARunnersLife #sixstarfinisher #RunnersLife #runnersofinstagram #londonmarathon #londonmarathon2022
Day 7 of rehab.
Currently negotiating with my ankle like it’s a hostage situation.
Got the backup of @itsmyphysioadrian and @therunningroom in this fight 🙋🏾♂️😆
Rhythm is what matters in a marathon block.
Not forcing things. Not chasing every run. Not ignoring the signs when your body asks you to back off.
After my 9th London Marathon, this year reminded me that consistency isn’t about doing everything perfectly, it’s about adapting, staying patient, and finding your flow again after injury.
Been running in the Cloudmonster 3 Hyper l light, responsive, and built for keeping that rhythm when it matters.
(Clip from before London.)
@on@runnersworlduk@runnersworldmag #onambassador
The rebuild starts here. Working with @itsmyphysioadrian at the @therunningroom
MRI next to properly assess my leg, with concern around a possible fracture.
Frustrating, but this is life, I’ll focus on what I can do until I get the result.
#ShotOniPhone
I’ve run 39 marathons.
10 under 3 hours.
29 over 3.
Does that make 29 of them failures?
No.
I ran injured for more than half of my 9th London Marathon. I’m proud I found a way to finish, because not everyone got that chance.
I’m still not running because of it.
London had records, PBs and incredible stories.
But this is for the people still processing theirs.
If your race didn’t go to plan…
if you got injured…
if you didn’t finish…
That is not failure.
Failure is letting one result decide your value.
You showed up.
You pushed your limits.
That matters.
If this feels like you, watch this 👇🏾
🎥 @giannis_an34 via @nba
📸 @adrianvarzaru cover photo
Four sub-3 marathons. One small England Athletics club. London Marathon 2026.
John ran his first marathon. Sub-3 on debut.
Proud to have coached Simon to run 2:56. A marathon PB in his 50s.
Ayo ran 2:54. The fastest finish time today from 1RC.
Rich went sub-3 again, just weeks after Manchester.
Four sub-3 marathons from a small club. Definitely proud of what the guys did today!
That doesn’t happen by accident.
It happens through consistency.
Through good people.
Through turning up, week after week.
If London Marathon 2027 is your sub-3 goal, come and train with us.
No ego. No shortcuts.
Just the right environment to help you get there.
Message us SUB 3
📸 thank you @jerry_sun@londonmarathon
London number nine.
Injury early.
Shuffle from 11 to the finish.
Not the day I wanted.
Still grateful for the chance to do it.
Thank you to everyone who supported out there.
London Marathon week, in pieces
Flat lay / kit & kids custom socks
Kids mini marathon
Apple Watch Ultra 3
On LightSpray Tour London
Music
Moments
Plus the closing message
#londonmarathon2026 #onambassador #applefitness
