I know this was “only” number four but I’m beginning to suspect I may never be able to put my finger on precisely what it is that draws me to marathon running.

Wanting to tick the box of doing one still seems entirely logical to me but the lure of going back for more far less so. I thought about this a great deal over the latter half of Sunday’s race in London.

The run didn’t go entirely to plan and I can’t say I enjoyed much of the second half. And yet, less than 24 hours later, I am sitting in a friend’s house barely able to move but with a decidedly positive feeling about the whole experience.

It just takes a quick look through the pictures of me on the official MarathonFoto.com website, however, to recall how miserable I felt as I revised my target down from staying with the 3:45 pacemakers to not walking and beating the times I did for my first two races.

I managed to do both, and finished in 3:51:54.

It’s certainly hard to imagine that anyone who saw me over those last few miles or immediately afterwards would have accused me of holding anything back.

Through my slowest mile, the 24th, I felt and, to judge by the photo, looked absolutely dead on my feet. My progress, then, through the finish area on the Mall was repeatedly halted by the need to lean on things for long periods after which there was the tragicomedy of trying to change in a nearby carpark.

Pacing
The atmosphere before the start was terrific. My plan, as I say, was to follow the 3:45 pacemaker who, I presumed would simply knock out 26 miles at 8:35, a pace I was fairly confident I could live with. The first mile was virtually spot on, 8:33, and I was thrilled by the prospect of getting around without having to worry about speed.

Pretty soon, though, I realised to my horror that despite having gone twice before the start, I needed to take another leak. I spent some miles weighing up the options and decided I couldn't spare the time to wait at an official toilet stop so I tried to build up a lead on my pacemaker before, at mile nine, diving into some bushes to relieve myself. It was all done with the urgency of a Formula One pitstop but the bottom line was I'd run a few fast miles getting ahead of the pacemaker and a few catching up with him after which he unexpectedly chipped in a few fast ones of his own.

Slipping
It took a while for this all to take its toll but from mile 19 on I started slipping badly with the number of people passing me compounding the sense of demoralisation. From then on, I had to dig in just to keep going.

Along the way, of course, there were some terrific highs and great sights though at times I was really far too preoccupied to take them in. I hope, however, to make it back some day, although . . . as I write this, it occurs to me that I could use the experience to achieve a better, faster Dublin marathon this October.

I think I might need help.