Like most weeks on an HF Holiday at Glencoe the ascent of Ben Nevis was on the walks programme: this week I had been allocated the job of leading the walk. By breakfast on the day nine guests had signed up, ranging in age from about 20 to 75. I’d walked with them all earlier in the week, the forecast was fine and dry with just a possibility of mist on the summit, and our route was the “tourist track” from Glen Nevis. What could possibly go wrong?

We left from the car park by the Visitor Centre and followed the path by the river until it turned uphill to join the path on the east side of the glen about 200 metres from the Ben Nevis pub. We stopped while I explained that our walk would finish at the pub where the coach would pick us up at 5 o’clock, hopefully after we’d had time for a celebratory drink.

The climb was unremarkable apart from one of those bizarre Ben Nevis events when, not far into our day, we heard a commotion behind us as we were overhauled by a group of firefighters. They were wearing full protective gear and some had breathing apparatus as well. They trotted past us, the breathing apparatus amplifying the puffing and gasping. It turned out they were from Ealing (or somewhere like that) and on a training exercise. Hours later, still on our way up, they passed us on their way down.

And so the day progressed. Half way up the zigzags we were almost in the mist so we stopped for lunch, then pushed on to the summit. Everyone was fine: some a bit tired, some a bit aching, but all in good spirits. We stayed about half an hour while the mist came and went, giving us views now in one direction, now another. Then it was time to go.

As we started down the main descent onto the zigzags it became obvious that I’d got two groups, not one. There were six greyhounds who were eager to get down as quickly as they could, and two whom I privately dubbed the ‘halt and lame’ – a 30-something man with a knee which became very sore as soon as the downhill started, and a man about 60 who despite his two walking poles lacked confidence on the stony path and needed to move slowly and carefully. It soon became clear I wasn’t easily going to be able to keep these two groups together.

But the weather was fine, we were out of the mist, the path could hardly be clearer. I gave the greyhounds permission to go ahead at their own pace as far as the path junction above the lochan we’d passed on the way up, where they should wait for me and the others. The four of us – me, the two halt and lame, and a young woman who was happy to keep us company – made our steady way down.

So far so good. We arrived at the path junction, the others hadn’t waited too long, everyone was OK. No reason not to do the same again for the last part of the walk. I reminded the greyhounds we’d seen the pub on the way up – all they had to do was follow the tourist path until they saw the pub and go straight to it. Anyone with any problems should just wait on the path for me and the other three to reach them. Off they went.

As the four of us eventually came in sight of the pub I guessed we were 10 to 15 minutes behind the others, an estimate confirmed by the nearly empty glasses on the table in front of them. But instead of the cheery “What are you having?” I felt I deserved I was greeted with a chorus of “Where’s Dan?”. “With you”, I said, suspecting a wind-up. “No, he was behind us. We thought you’d pick him up.”

I’d never lost a guest before. I quickly established that Dan had been fine, but had found the greyhound pace a bit fast so had lagged behind. I reckoned he couldn’t have had a mishap: there were plenty of people around, there would have been a bit of a commotion, he’d be by the side of the path. So where was he? How could he just vanish? I could only think of one explanation. About a mile back up the track a path goes off to the side, leading to the Youth Hostel down in the glen. You hardly notice it on the way up, but coming down you see the junction and the path below is in clear view. There’s even a sign to the hostel. Dan must surely have gone down there by mistake. So how to find him? What would he do once he realised he’d lost us? He’d either stay put, walk back up the hill (less likely), or walk down the glen road to our morning car park.

Weighing up the options I headed for the Visitor Centre car park and asked after a smallish American man in his sixties wearing a bright coloured t-shirt. He hadn’t been seen there, so I started up the road hoping to see him coming towards me. They hadn’t seen him either at the Café Beag a mile up the road. Slightly anxious now I carried on towards the youth hostel when, round a bend, there he was. We were both relieved, each for our own reasons.

A mobile phone call broke the news to the rest of the group still at the pub and arranged for us to be picked up in Fort William. A second call told the HF house all was well. An offer of a lift into the town from a waitress at the Café Beag going off duty was accepted with gratitude, and within 15 minutes from meeting we were sitting on a bench in Fort William waiting for the coach.

Dan’s story was as I’d guessed. He was walking on his own and just followed his feet downhill. He never saw the path junction, and was down at the road before he realised he’d gone wrong. He was still debating what to do when I came round the corner. “I’m so glad I found you in time”, I said. “The paperwork I’d have to fill in if I’d lost you is unbelievable.” “If anyone asks”, he said, “let’s just say I was ‘temporarily mislaid'”.