Marathon Mania blog: 4:32:27 - three little numbers that don't even start to tell the story

But it was never about a fast time for me, in my first 26-miler, no, it was just about getting across the finish line in one piece.

And just one mile into the race, this approach was crystalised further when a man directly in front of me collapsed to the ground in a heap, hit his head on the pavement and started having a seizure.

It happened on perhaps the only stretch of the entire course that was not flanked by either spectators or stewards. It could potentially have been very serious indeed.

About six of us stopped running to help him and wait until assistance arrived. It was a sobering sight. From that point on, the only thing I wanted to do was finish without damaging myself.

It can be tempting to push yourself beyond your limit in the hope of attaining a fast time, and risk injury, but for me it just wasn't worth it. Instead I sought to enjoy the experience. One I knew I'd probably never do again.

My pre-race preparations were a careful balancing act. You want to drink enough to be hydrated, but not so much that you need to pee during the race. I slightly overdid it and had to pause to relieve myself on mile two. It was another delay that quashed any lingering hope I had of finishing in under four hours.

On six miles came my favourite moment of the race. A sole spectator was holding an Ipswich Town umbrella. I rushed over, shouted "Tractor Boys, yeah!" and high-fived him. When anything like that happens, it gives you a huge boost.

At 12 miles two of my friends were on the pavement outside Bermondsey Station, again, a huge boost. It really does make a difference to see supporters in the crowd and it is part of what makes the London Marathon such a joy.

Running over Tower Bridge was a special moment, but was also the point where the pain began to really kick in. Rather than any peaks or troughs, I found that the pain just got progressively worse with each passing mile.

My mum and dad were stood at mile 17, it was great to see them, but I think that was the last point at which I could say I was really enjoying myself. It was a battle against pain from then on.

At mile 20 I tried to pick up my pace slightly in an attempt to get home in under four-and-a-half hours. But the running traffic was so dense it made overtaking very difficult.

At this stage many were also walking the course, and it was a case of weaving in and out to avoid them. I'm certain that because of this, it must have added at least an extra mile to my total race distance. Following the 'racing line' like the elite runners do was impossible.

From mile 23 or so you are following the banks of the River Thames and while the pain is excruciating, the sights and the huge crowds cheering you on is what keeps you going. My legs were jelly but I knew that if I stopped to walk now, I'd be walking the rest of the way.

A big group of my friends were stood under Cannon Bridge and I simply hugged them and said: "I want to die." There was no energy left, I was like a zombie just throwing my legs in front of me.

I overtook two guys running in a horse costume and I heard the front say to the rear: "It's just about grit now." Indeed it was.
I don't often look at the House of Commons and feel relieved but this was a sign that the end was definitely close. And yet, when I reached The Mall and saw a sign saying "800 metres to go" I still thought I might not make it.

Crossing the finish line almost brought me to tears. Then I was given a goody bag that had so much pointless free stuff in it that I could barely carry the damn thing. I sauntered on to collect my belongings, meet my parents at Horse Guards Parade and then on to meet my friends in a pub.

Only when I tasted that first pint did I feel the deep satisfaction of an achievement that will go down as one of the toughest I will ever accomplish in my life.