London was not the only city to host a marathon last Sunday and, it can be argued, neither was it the most interesting, despite the presence of Olympic hero Mo Farah.

In North Korea, 800 professional and amateur runners were at the same time lining up inside the Kim Il-sung Stadium ahead of Pyongyang's 27th annual marathon. Open to overseas recreational runners for the first time as part of a wider initiative to boost tourism, this was a historical moment for the world's most secretive nation.

I have always wanted to see North Korea but did not much fancy being part of a heavily restricted group tour, as is the case with visitors. So here was a chance to gain relatively free access and burn a few calories too.

It proved easier than expected to sign up – about 300 of the 800 people who took part were non-North Korean – and, to my relief, the clusters of people around me at the start line did not look like actual runners.

This was the first time North Korea had attempted to organise a marathon on this scale and it would be fair to say the preparations were a shambles.

Having released limited information prior to the event, besides the five-hour cut-off time, the organisers then left it until the night before to announce rather significant tweaks to the schedule – most notably that the closing ceremony would get under way four hours after the start of the marathon.

Last-minute changes
There were other last-minute rule changes, like no snacks, cameras or music devices, and no large logos on clothes, no American or Japanese flags and specifically no apparel displaying the word "America". "Don't worry about not having photos, we have men to shoot you," one poker-faced official said to a stunned set of tourists.

Fiona Pascall, a pilates instructor from Bristol who had spent months training, agonised over whether she would be able to complete it in four hours.

I had no such concern – there was absolutely no way I’d make the newly imposed deadline and thus I became part of a group of competitors who regretfully (but secretly gladly) had to back down to the half marathon.

After an initial awkward false start, when no one quite knew which was their signal to go and 225 amateurs had to shuffle back 50 metres, we were finally let loose in Pyongyang.

The run itself consisted of four loops (two for the half marathon) around a section of the city. It gave runners the change to take in several humongous communist monuments in all their pristine glory. We also caught rare glimpses of basic- looking flats adorned with portraits of the great leader and an occasional unidentified animal hung up by its heels for dinner.

The lack of security lining the streets came as a surprise, as was being able to travel freely from the boundaries of strictly supervised tour groups. For once, visitors to Pyongyang were not being shuffled around a glitzy national building or feeling compelled to bow down in front of imposing Kim statues.

Scattered along the route, hordes of eager supporters clapped and waved as we trundled past, providing a motivational boost. Elderly women flashed their gums as men in grey communist suits and school children high-fived us, giggling at our red faces and short shorts.

There was support, too, for the young Korean girls with bowl haircuts who streamed past in whimpering pain, pushing themselves to their limits, and even more so for national hero and Pyongyang marathon-veteran Pak Song-chol, who was egged on by a moving car blaring out nationalist propaganda as he unceremoniously lapped me and others on our second trek of the course.

I remember being struck by the sense of normality in the faces of the excited onlookers. Suddenly, the world’s most secretive and feared nation had an unexpectedly welcoming appeal, which was amplified by the sound of 50,000 people cheering on the runners as we re-entered the stadium.

Completing a victory lap in a fashion akin to Jessica Ennis winning a gold medal, I finished the half-marathon in two hours and 12 minutes, just in time to see Pak tearing over the line to raptures of applause – and why not, given he had completed his race at exactly double my pace.

Stadium gates

With the schedule running late, the stadium gates were just drawing shut when Pascall came bursting through – becoming the first and only amateur woman to complete the route on time. She came home in four hours and one minute.

The closing ceremony saw the chairman of the National Marathon Committee hand out awards, with fits of laughter erupting whenever he struggled to pronounce a foreign name. It had been a monumental day and soon we were off to revel in our victories at our Olympic village replacement – one of Pyongyang’s legendary micro breweries.

Guardian Service

Isobel Yeung is a freelance writer and TV reporter based in China.