It just about flippin' did me in

Apologies to the geese and sheep of Oxfordshire for my exhausted rants on the Thames Path Challenge ultra marathon. It turns out that covering 65 miles in one go can send you completely nuts.

Thank you so much to everyone who supported me in raising £1,550 for Cancer Research as I somehow managed to finish the 100-kilometre Thames Path Challenge ultra race at the weekend. It's far and away the hardest physical thing I've ever done and it just about flippin' did me in.

After only 10-12 miles, I started to develop horrendous blisters (I'd over-trained in the weeks before and not allowed my feet sufficient recovery time). Also, it didn't help that I forgot to take a water bottle with me – I eventually had to fish one out of a bin and ask a stranger to rinse it out for me. I mean, c'mon Frase, this is not professional! My other mistake was to take Ibuprofen to ease my foot pain – not good for the stoimach

Some amazing people actually RUN the whole race but I was among the majority who walked most or all of it, setting off early on Saturday morning from Putney. It's a stunning route following the River Thames all the way to Henley – incredible views, and the weather was perfect.

But it got really tough after the sun set. The blisters on my feet made every step painful as I plodded along in the middle of what felt like nowhere. It was pitch dark, very foggy and the remaining field of weary competitors had long since dispersed. I mostly just had the odd sheep or goose for a companion, and I don't think they enjoyed my attempts at conversation. But amazingly, despite having taken a few wrong turns earlier, I didn't get lost in the dark. The illuminated way markers kept me on track and I stayed close to the river.

I had my feet re-dressed for the second time by a wonderful first-aider at a rest-stop around midnight, but was also feeling pretty sick by this point and couldn't keep any food or drink down. To be honest, I think I went a bit mad for sections of the last 10 miles, and can't remember much about it. A volunteer had to come running after me near the end having noticed that I had inexplicably taken a wrong turn. Eventually, however, I crossed the finishing line at 3.40am (20 hours and 39 minutes after setting off). According to my Strava app, I had covered a total of 66.5 miles.

I believe that just over 700 of us started the full 100km and I finished 220th out of the 556 finishers, which is way better than I ever hoped for.

Having said that, the worst was yet to come. After picking up my bag of belongings I had to hobble another half a mile to the hotel. I was in a really sorry state the next day.