What’s it like to walk 80km in a straight line – across some of Britain’s biggest mountains? Not straightforward, as Calum Maclean found out…

Main image: Calum and Jenny taking on one of the many unforgiving inclines. Photo: Johny Cook 

What’s the longest line you can walk along in Britain without having to cross a paved road? In 2018, the Ordnance Survey officially blogged an answer to this intriguing question – it was, they said, in Scotland: a 78.5km (49 mile) route between the Pass of Drumochter and Corgarff in the Cairngorms.

At the end of last summer, adventurer and broadcaster Calum Maclean teamed up with record-breaking round the world cyclist Jenny Graham to attempt this fabled journey, ideally without straying more than five metres from the line. The result was an inspirational, funny and honest short film, The Longest Line, which has recently been made free to watch online.

Hanna Lindon snatched a few Zoom moments with Calum between his filming commitments to talk intense navigation, 1mph walking and intriguing new discoveries.

Where are you at the moment? Looks beautiful! I’m doing some filming for SpeakGaelic on the island of Eriskay. [Turning the camera to let TGO see] Look at that, it’s beautiful. There’s a game of football going on down there and Martin Compston from Line of Duty is playing in it. I’m filming here all week – today we’ve been filming Eriskay ponies.

Sounds amazing. But back to last summer’s adventure… how did you come up with the plan to walk the ‘longest straight line in Britain?

I didn’t invent the idea myself. Someone on Twitter asked the Ordnance Survey what’s the longest straight line you could walk in the UK without crossing a paved road. They wrote a blog about it, which had been online since 2018. Some people had tried it, but – as far as we knew – nobody had ever completed it. Matt and Ellie from Summit Media approached me and said: ‘we’ve heard of this, fancy trying it?’ At first I was like: ‘dunno, do you fancy trying it?’ But I got caught up in the challenge of it. I didn’t know how it would turn out and that made me feel like I couldn’t say no. Maybe I was naive! I thought: ‘well, it’s not that far, I’ve been there plenty of times’. But the idea you have of walking in a straight line is very different from the reality!

Did you hear from any of the people who had tried it unsuccessfully before you took on the challenge?

We did find a blog by another group who had tried it. They set out in the opposite direction, but they had really bad weather and they only managed a couple of days. There was another group, too, who had shocking weather. From what I could see, it didn’t look much fun. Straight line walking is all about being focussed on the mission of strictly following the line as closely as possible.

When did you set out on your expedition?

It was the end of August last year. We were mega lucky, the weather was perfect. There was no rain, barely any cloud, it was warm, but not too hot. Weirdly, too, there were hardly any midges, even though it was quite ideal conditions for them. If it had been cloudy and wet and you couldn’t see anything, it would have been really dire.

The pair enjoyed some forgiving August weather. Photo: Johny Cook

It must have required some seriously specific navigation. Did you use a paper map, or did you go digital?

We took both options. I started with the map and Jenny with the handheld GPS device. Within 40 minutes we ended up putting the map away and just went with the GPS because it was so slow! Walking on a bearing is fine if there are loads of trees and big, obvious rocks, but when it’s a hillside covered with heather that’s really hard. The GPS device had the line on it, and because you could see where you were you got the immediate feedback when you went off the line. That was good, because we could stick to it more closely. But it was also more stressful, because we could see immediately when we made a mistake. It sort of felt like we were being controlled by the line.

How does it change the feel of an adventure in the mountains adding in that extra element of insanely intense navigation?

It totally changes it. This was unlike any other kind of walk I’d done – for a couple of reasons. First is almost being glued to this GPS device, because you’re checking it a couple of times every minute. Add to that the actual terrain… well, you never get a chance to just relax and walk. When you’re on a path you can enjoy what’s going on around you and take it in. But walking like this you’re constantly having to correct yourself and think about where you are. I’ve done very short bits of walking on a bearing during winter and for navigation practice, but this was something else.

What were the hardest obstacles you faced in the terrain?

Luckily there was never anything that put us in danger. Because we were lucky with weather, the rivers were low. The River Feshie in particular would have been sketchy if the weather was bad. The trickiest bit was probably coming down some scree slopes as we descended Beinn a’ Bhùird where 20 or 30 metres to the right there were these huge slabs. We were incredibly lucky that the line took us right beside these crags without venturing onto them, because we would have needed a rope and harness to climb them and we hadn’t brought anything like that to keep our packs lightweight. Generally, everything was walkable – there was nothing that had to be climbed.

How about scrambling?

For sure, scrambling. There was some really steep ground where you had to use your hands occasionally and do a bit of bum sliding. There were a few slabby bits where you were almost climbing, but if you’d have slipped you would only have slid down three or four metres.

The route involved some careful navigation across featureless terrain. Photo: Johny Cook

Did you end up exploring bits of the Cairngorms you’d never visited before?

Yes! There were gullies and gorges you’d never normally get round to going to because they’re not on the way to a hill or a loch. We discovered a couple of really nice little gullies – I had a plunge on the first day in a small pool, and then on the second or third day we walked into a beautiful gorge round the back of Glen Feshie. On the third day of the walk we also went through upper Glen Derry –  I’ve never been there before and it was absolutely beautiful, with all these really old pine trees.

You say at one point in the film that you’ve been walking less than a mile per hour – was that typical of the whole expedition?

That was probably our average pace over the whole thing. There were a couple of bits where it was empty, hard, peaty ground and we got up to almost 3mph – normal walking speed – but going up and down the hills was almost laughably slow.

Did the slow pace make the whole thing harder to plan?

Yes, especially because we didn’t have experience of exactly how it would work. We were slightly ambitious on a couple of days about how far we’d get and we got benighted. We finished the whole thing in the dark, too, which we didn’t expect – we’d started nice and early. We could probably have gone faster sometimes but the film crew were trying to leapfrog us and we were trying to work out where one another were, often with no signal.

Did the film crew walk the whole way with you?

Yes. Basically, as soon as you’re three-four miles into the walk there’s no easy or fast w ay out! They walked longer than us, worked harder, carried more weight… but they weren’t always going in a straight line.

In the high reaches of the Cairngorms. Photo: Johny Cook 

What was it like seeing the car at the end?

Satisfying. You could see it maybe a few miles away in the distance. We’d had enough of the straight line walk at that point so it was a good feeling. Although the actual end of the walk was quite underwhelming because there’s really nothing around – it’s just an empty road, no café, no people, no nothing.

Would you be up for taking on another straight line challenge at some point?

If Jenny came to me with an idea, I think I’d be almost honour bound to say ‘let’s do it’, because it was me who recruited her to do it this time with only a week or so’s notice. Otherwise… well, you know what, I’d definitely do a day-long one that involved finishing with a mountain top, or maybe a nice swim or a pub.

Were you chuffed with the film?

I wasn’t sure how it would turn out, but I think Matt and Ellie did a good job. They cut out lots of our moaning, to be fair. In the longer cut there would be more of me being grumpy. When we did the walk we thought nobody else had done it before, but afterwards somebody got in touch to say that they’d done it during the late’70s plotting it themselves using maps. Really, though, I didn’t care if anybody had done it or not, it was more about looking for new challenges, especially after the last two years with everyone walking in circles around their house. I think the film summed that up and I hope it inspired someone else to try to take it on!

WATCH: The Longest Line on Youtube, produced by Summit Fever Media.