A thick layer of pollution had been hovering over London for the past few days. So it was fitting that, as I boarded the Eurostar on Friday morning, I was heading to Paris to do a race that took its environmental responsibility very seriously.

The EcoTrail 80k trail race starts way out of Paris and winds it’s way towards the centre of the city, finishing on the first floor of the Eiffel Tower. Despite being in a major city, 90% of the route takes runners through woodland trails interrupted only for a few road crossings.

Just before mile 7, we emerged from some parkland to cross a road. Marshalls had stopped the traffic so we could run across without stopping and cars had backed up four deep on either side. The Parisian drivers vented their frustration the way Parisian drivers do best and leant on their horns. The woman running alongside me laughed and said something I didn’t understand. I shrugged “Je suis Anglais.” She mimed pressing a horn “Meeeeeep”. We both laughed.

Moments later we ran down some steps through a housing estate with a hedge maze below us. The race organisers had resisted the obvious joke of making us navigate the maze before continuing, but one runner couldn’t resist another urge and nipped into the maze to answer the call of nature.

My watch beeped. There were still 41 miles left to run.

I’d come to Paris to run a long way. I knew it would be hard. I’d thought about how my legs would cope. How heavy they’d get. How I’d be hungry and tired and possibly cold or wet. I’d prepared for those. I hadn’t prepared for how heavy the weight that thinking how far I still had to run would be.

The first checkpoint came at around 14 miles. As we ran down a hill the noise of music and cheering came at us through the trees, getting louder. I ran into the checkpoint, ate some peanuts and went into a building to use the toilets. Inside at the medical station was a British woman I’d met on the way to the start and run the first few miles with. She’d hurt her hand in a fall but was going to continue.

I set off again, aware for the first time that despite being surrounded by 1,500 other runners, this brief exchange was the first time I’d spoken to someone in the past two hours. I turned my phone on and there was a flurry of messages from my Team Rainbow friends in a group chat as they watched my progress online. They made silly jokes, and I replied with a picture of me pulling a face and a complaint about the hills. Liz countered with a picture of the two laptops in front of her. The trees and the hills weren’t so bad.

The trail ahead was heavy with runners. At times I wanted to run faster, but there was no room to overtake. I told myself I’d probably be grateful for this involuntary pacing in the later stages and tried not to get frustrated. When we got to the downhill sections I pushed myself down, I wanted the free speed that they gave and had learnt the hard way in Snowdonia how holding yourself back on a downhill is more trouble for your quads than it’s worth.

In many ways Paris was the culmination of every race I’d done before it. I guess that’s true of every race we start, but it felt particularly true for this one: the Flitch Way marathon with it’s long, straight trail that never seemed to end; Snowdonia Marathon with it’s steep ascents and descents and the Iron Person once the sun went down and the only thing to be seen was the circle of light just ahead. In that respect, it felt familiar despite being a long way from home.

In all those races, though, I’d had friends with me. Someone to share a joke with and laugh at what we were doing. Someone to help the miles tick by. In Paris I felt very much on my own.

The second checkpoint was past marathon distance at 45km. It was at an observatory on the top of a massive hill. It had water and our first glimpse of the Eiffel Tower where we would finish. It had started to get cold, so I put my jacket on, put my headphones in and got moving again.

The race had started at midday and had a 1:00am cut-off. I was hoping to make it round in about 10 hours for no other reason than that 10 hours seemed long enough to spend running. 7pm came and went and the sun went down. I sang along to Meghan Trainor on my headphones, if I couldn’t talk to anyone, then I’d sing to myself instead.

As we pulled into the penultimate checkpoint it was dark and the Eiffel Tower lit up in the distance looked no closer. I put my head torch on and carried on. The 14km to the next checkpoint were a blur of darkness and trail that made it slow going.

At the last checkpoint, 17km from the end of the race, I was cold, tired and angry at another competitor who’d made fun of me. He’d come into the checkpoint behind me and asked in French whether the container in front of us has sports drink or water. I understood his question but it took me a while to string a few French words together to answer. He laughed at me, said something I couldn’t understand to the other men stood round and they all laughed at me.

I walked away wanting to cry. I turned to my phone and more messages came through from the Team Rainbow girls and some texts from my family. From the top of the Eiffel Tower a searchlight blinked out across the city calling the runners home. I could see the river not far away and knew that once we got there it was all flat to the finish. By the time I hit the river I wasn’t upset, I was angry. Every person in front of me was, in my mind, the man who made fun of me. I started running. Properly running. He wasn’t going to beat me to the tower.

I ran hard along the river. My watch kept beeping up at me as the miles ticked by. The tower got closer and I glanced down to see an 8:45 mile. I overtook a lot of people. It was the first time all day that I felt like I was properly running and it felt good.

After more than 10 hours I was at the foot of the Eiffel Tower, ready to climb to the first floor. I saw Phil in the crowd, I was handed a ticket and I climbed the stairs. I felt sick, I felt dizzy and my legs screamed. But finally, I was done.

Thank you to my fiends and family for all the messages. I couldn’t have done it without you.

EcoTrail Paris gave me my entry to this race. It was very well organised with signage throughout. There’s also a 30k and 50k option which both finish at the foot of the tower. If you’re into stats and routes, here’s the Strava data for all but the last couple of miles.