Without doubt, one of the hardest days I’ve ever had. A 12-hour epic, starting and finishing in the dark: 80 miles of cycling, 17 miles of walking, three Munros.

Stage one was a 40-mile ride between Inverness and Glen Affric, via Drumnadrochit. I left my cycle at Affric Lodge and followed the easy path into Coire Leachavie, climbing up to the col between Mam Sodhail and Ciste Dubh. I quickly gained Mam Sodhail and then Carn Eige, the highest point in the old county of Ross and Cromarty.

I continued north, down Carn Eige’s steep, rocky slopes, to the mountain’s north top, before grinding up Beinn Fhionnlaidh, which overlooks Loch Mullardoch. The Munro-bagger in me couldn’t ignore Beinn Fhionnlaidh, but I would pay for this 3.5-mile out-and-back diversion later in the day.

Back on the summit of  Carn Eige, this time I descended its east ridge over a series of tops. I’d read about a path that drops down into Gleann nam Fiadh, but couldn’t remember where it left the ridge. Typically, I turned off early by An Leth-chreag, convinced I’d already missed it, giving myself an uncomfortable descent of precipitous slopes, then over gloopy bog, to finally meet the track.

The glen was sodden. I might just have well been walking down the river. My socks were soaking wet, causing very painful blisters on both heels – so painful they kept me awake at night. Eventually, the track takes a sharp right, turning due south along a drier, stony path. It climbed gently over the moor to a height of about 500 metres, before Loch Affric appeared below.

It was 4.30pm. Darkness would be upon me in two hours – and there was no way I was going to cycle 40 miles in two hours. I returned a different way, following the road that stages the annual Highland Cross to Beauly and then the Moray Firth road to Inverness. I began to bonk still 25 miles shy of Inverness. Light-hearted and shaking a little, I ate a Mars Bar, Tablet and, strangely, a sausage that I had left over from lunch.

I felt marginally better. It was already dark as I met the Beauly-Inverness road. Despite putting batteries on to charge overnight, my front light didn’t work. Unless you’ve endured mammoth days like this, you won’t appreciate the emotions that stir when you see your destination, in this case the bright lights of Inverness and the Kessock Bridge.

I bonked again in Inverness and even though there was less than three miles to go, I felt like I couldn’t go on. Stop being a wimp, tough it out, I thought, as I swallowed an entire pack of Jelly Tots in one go. Home and time to put on a front: ‘Easier than I thought, could have gone on for another 20 miles if it wasn’t dark.’ My stumbling stride and hollow face probably gave the game away.