Stage 4: 81.5km (50 1/2 miles)

About half way down the HUGE dune

And it arrives! The day of doom.

Tried to think positively (see my PMA training has paid off!) by thinking of those poor people whose feet are much worse than mine.

I've been religiously getting my blisters cleaned and taped by Doc Trotters each evening and am starting to see the evidence of some severely wounded feet. Mincemeat comes to mind.

So with that positive thought tucked safely in I set off.

As usual we started to jog to the first checkpoint but hat the stop as got too hot. I see a theme occurring here...

Pre checkpoint 1 we had to climb a long, steep rocky ascent, followed by the most fun I've had out here - a technical descent down the biggest sand dune I've ever seen. The organisers had to add a rope to hold onto to descend, but many people just ran down. I'm sure some of them would have lost their footing and rolled down. Faster I guess at least.

Trotted through some flat rocky plains to reach checkpoint 2. I had noticed my left ankle had started twinging. I tried to ignore it. Mind over matter. But unfortunately it got progressively worse.

I stopped halfway through checkpoint 2 to try and tape it up. Then at checkpoint 3 I had to ask them to tape it some more and supply me with some strong painkillers.

So frustrating.

This is the thing I've found about Marathon des Sables. It's not really all about fitness. It is a bit about luck. You may get blisters. You may not. You may get dehydrated. You may not. You may develop shin splints when you've never had a problem with them before. Or you may not. It's a bit of a gamble.

You can either go for it and be a competitor, and risk not finishing. Or you can err on the side of caution and be a completer - hobbling through it all come what may. There were a lot of teeth gritted out there let's say!

One of the high points of being a completer rather than a competitor was on day 4 the elites set off three hours after the rest of the field, so at around 1-2pm you see them all overtaking you.

Pretty incredible to watch them. My favourite, other than the legend that is Ahansal, was our incredibly talented Jen Salter. Women do tend to do better the further they run, and Jen is outstanding. Felt very proud to be British and a woman as she raced past.

And then I went back to my comical hobble/shuffle.

As the sun started to go down, we all entered the twilight zone. And dunes. Bastards.

I started to fantasise about sleeping while hobbling again, and begun to see motorway bridges. Not quite sure why. I kept thinking I was running underneath the M25.

More painkillers at checkpoint 4. And on. If it wasn't for the better half I think there is a chance I may have given up here. I was in pain, tired and tearful. My leg had ballooned.

We trekked on as we entered the dark phase (in more ways than one). The headtorches came on. The glowsticks attached to our bags. We past people kipping in their sleeping bags.

Along the way we gained a friend. A Korean man tagged onto the back of our train. I think he was feeling a bit low as well and wanted some company. Was quite touched on reaching checkpoint 5 that he wanted a photo with us. The most I could muster through those kilometres was a few grunts and shouts of pain.

I think the better half secretly enjoyed this phase as at one point we had a train of around 15 people with him leading the way. I heard the word "marines" mentioned a few times.

We made the not-difficult decision to get our heads down at checkpoint 5. I was really upset by this as I wanted to get it finished, but my leg was having non of it. We ended up sleeping for 7 hours which became a bit of a joke among our friends. And probably for those at home who know how much my better half and I love our sleep!

5am we carried on. Some malt loaf, salt tablets, immodium and painkillers were order of the day! The morning was a different story. It was light. We felt refreshed. It was cool. So we managed the last two checkpoints in record time and got in before 10am, giving us a full rest day, and having had some kip.

Seeing and finally crossing that finish line was stupidly emotional. The race wasn't over, but I was in bits. I was so relieved I hadn't given up. I was so grateful to the better half and I was so bloody relieved to stop moving!