On 1st September, 2007, I took part in my first triathlon. After accepting a challenge from a colleague from work and roping a client in, I had planned to prepare for the 1.5km swim, 40km ride and 10k run with intensive swimming coaching and loads of summer evenings out on a new bike. Only things didn’t work out that way and I went in to the event woefully ill-prepared, but determined to finish the damn thing. Here’s what happened on the day…

I’m staring at the sea, surrounded by loads of very lean looking blokes in black wetsuits and identical yellow swimming caps. It’s like an out of body experience: I don’t know what the hell I’m doing here. I’ve always been a poor swimmer and this is simply stupid.

There’s a five minute warning to start the triathlon. I’m scanning the horizon, trying to work out where Armgard and Jo are amongst the ladies field, which started 10 minutes earlier. I think I can work Jo out. She’s at the back. Hmm, that’s a worry - she’s a much better swimmer than me.

There’s a two minute warning to the start. Some of the other competitors are taking a dip in the sea to get themselves ready. It all looks very serious.

My heart’s beating fast, but I don’t feeling panicky now (the previous two weeks were another story). I just want to start. Then, disturbing my day-dream with a jolt, we’re off and a couple of hundred men charge into the sea. I walk in, hanging at the back. There’s no point in getting in people’s way.

We have to swim out towards a yellow buoy, before cutting turning right, perpendicular to the coast and head a few hundred metres for the second marker, then returning to the coast with the tide, before doing the whole thing again.

Within moments, it’s quite clear I’ve bitten off more than I can chew. Everyone else is powering ahead with impressive front crawls, while I am at the back – the only competitor foolish enough to be swimming breast stroke. What on earth was I thinking?

I try a little crawl while swimming against the tide, soon tire and revert to breast stroke. I’m going to be in here a while. Never mind, as the character says in Finding Nemo, I’ve got to “just keep swimming.”

Once past the first buoy, the second seems permanently far away, with other competitors starting to lap me. Within a few minutes I here a familiar voice. “Well that’s both of us finishing last in the swimming.” It’s Jo, slowing to a breast stroke to check I’m alright, before continuing her crawl off into the distance.

Eventually I reach the second buoy and turn in for the third, positioned near the shore. One of the safety canoeists checks that I’m ok and I continue on my way.

If anything, the second lap is even worse. By now all the competitors, bar one or two, are out of the water and I have two personal safety canoeists following me around. I’m starting to get fed up with the taste of seawater now. The water has got a little choppier and the second leg of the triangle takes forever. As I come out of the water, all the supporters have long since gone and I get a good natured (sympathy) clap from the canoeists, who are getting ready for the sprint tri to start.

I’m supposed to run to the transition point, but I walk up the beach. I just feel sick from swallowing loads of salty water and a bit embarrassed. I’m at least 45 minutes behind the rest of the field. I remind myself that it’s the finishing that counts and I’ve done the hardest bit.

I quickly change out of my wet suit and put a pair of shorts, trainers, ipod and a t-shirt on, ready for the ride. I climb my bike and head for the next part of the course. Here we have to ride 12 laps of the two mile or so course along the coast. It’s relatively flat, just raising up a bit near the turn. Fortunately, there are plenty of competitors still out, finishing their last few laps.

I soon forget about my poor performance in the sea. It’s clear, though, that there are some serious athletes here, as many zoom past me riding at least 30 miles an hour (Jo later remarked to me that half the men had been shaving their legs; always a worrying sign). I’m not the slowest on the bikes, although I do get overtaken more than I overtake. It starts to thin out, then suddenly gets busier again as the sprint tri competitors, which followed my event, join the field. I remember my muscles getting tired cycling last weekend, so eat a couple of chocolate bars during this part of the event for fuel.

It’s during the bike ride that I realise the atmosphere isn’t the same as the half marathon I did earlier in the year. Maybe it’s because there are fewer competitors, therefore less support. Or perhaps it’s just that triathlons are for proper athletes, who take their sport very seriously. I wouldn’t like to know what they think of ‘have a go’ people like me.

Just over an hour on the bikes, completing my 12 laps, and it’s time to get back to the transition area for my run. My legs are jelly like, so I have quick stretch and an even quicker pee. No Paula Radcliffe action for my along the promenade - not with that coastal breeze anyway.

Within moments of starting my run, I’m really regretting eating the chocolate bars, as I have the worse stitch I’ve ever had. We’ve got to do four laps of the prom and within half a mile I end up walking. The best thing to do when you get a stitch is to slow down a bit. ‘A bit’ for me means walking, as I wasn’t running fast to start with. After a while it begins to ease off slightly (or I just get used to it) and I start to run again. As the field starts to thin out (even most of the sprint tri competitors have finished now) I start to see familiar faces crossing me on the course. But despite smiling and nodding to a few, nobody seems to return the compliment. Maybe they’ve got horrible stitches too? Or perhaps I look like a zombie? On my second lap I spot Jo sat on a bench, chatting to her folks on the phone, and she joins me for a few hundred metres (Armgard is having a post-race massage) and I feel encouraged to step the pace up slightly – in fact I’m actually starting to feel ok, the more the race goes on.

On my last lap, there are a few more competitors sitting with their friends, and most of them clap me to the finish. One of the race marshals, who was with the canoeists earlier, gives me a big clap and congratulates me as I come round the final bend. I feel a warm glow, and look forward to crossing the line. American Pie is playing on my ipod (bizarre choice, I know). As I approach the finish, the commentator spots me and calls out my number, 215, looking my name up. Although hashing the pronunciation of my name, I’m just hugely relieved that he doesn’t announce me as being the last classic tri competitor to come in. That would be too much.

Once I’ve finished, I’m happy but I don’t feel the euphoria that came with the Reading Half Marathon. It’s more a mixture of relief, embarrassment and the realisation that I’ve done the hardest physical challenge of my life, with relatively little preparation. I also come away with a commitment to find a swimming coach, once I’ve worked out where I’m going to live. I don’t know my time – in fact, I’m not sure I even want to know. It’s just good to have done it. And with only four weeks to go before the Great North Run, I’ve got long enough to make sure I’m better prepared for my next event. But I think it’ll be a little while before I venture back in the sea.

Now I’m back in Leicester, the whole thing feels like a surreal dream: did I really do a triathlon yesterday? A reminder is the race number sat on the table next to me as I type this up. In the style of Mr Benn, I think I’ll keep it, just as a reminder.