On 11th September 2011, I took part in the London Duathlon.

The London Duathlon is the world's largest Duathlon. It is held annually in Richmond Park, south-west London, completely within the confines of the Royal Park, which is closed to traffic for the day.

There are three main distances on the day:

The “Fun” distance of 20k which is made up of run 5k, cycle 10k, run 5k

The “Challenge distance of 35k which is made up of run 10k, cycle 20k, run 5k

The “Ultra” distance of 110k which is made up of run 20k, cycle 80k, run 10k

I chose the “Challenge” distance.

I arrived at least an hour and a half before my start time. You have to get your bike racked in the transition area and place your helmet and anything else you deem essential, in the optimum position.

They start you off in waves of 10 according to your predicted ability. This stops the paths from getting too congested. When I started at 10:40 there were already over one thousand people out on the course.

At some stages you share the road with the cyclists only separated by a line of traffic cones. You are running in one direction and they are cycling towards you!

When you turn off away from the cyclist, you can really begin to appreciate just how beautiful the park really is. You run past herds of deer just sitting around amongst the old oak trees and the bushes, giving you the strangest looks (The information pack advises you to give way to deer, whether on your bike or running. Apparently you’ll come off worse). There are also flocks of brightly coloured green parakeets flying around making their distinctive calls.

The first run of 10k went quite well. It was quite warm and sunny, but there was quite a wind and some rain clouds flew overhead, but they didn’t rain on us.

Then it was into the transition for the bike. There are two 10k laps to complete. You must remember to do both laps, or you’ll be disqualified. You would think that would be an impossible mistake to make, but some do.

After the first lap the rain suddenly came hammering down. This combined with the speeds people were reaching, made for some quite interesting moments. There are some pretty sharp bends and at the roundabouts the marshals are shouting at you to slow down. I got up to 38 mph – great fun, as long as you don’t come off!

Then it was back into transition, rack the bike and off on the second run - 5k. The rain had stopped and it was getting warm again. I was really done in, enjoyed myself on the bike a bit too much. I was only just aware of running/shuffling past the Royal Ballet School, White Lodge.

Eventually came up to the finish, collected my medal and met up with my wife Eva. We collected the bike from the transition zone and headed off back to the car. There were still people streaming in, arriving for the “Fun” event in the afternoon and the “Kids” event as well as relays.

The whole thing is really well organised and probably the only time you’ll get to cycle around the roads of Richmond Park when there are no cars.

I completed it in 2:11:52 – it’s a really great fun event. I really like the run-bike-run format, mainly because I swim like a stone and a Tri is out of reach at present. I’d recommend a Duathlon in general and this one in particular to anyone.