It can also be deceiving on the way down. I trudged on until mid-morning.

It was an enormous struggle not to give up. What was the point of carrying on? I had had a reasonably long life. Sixty-five wasn’t that bad. It had been satisfying. Why not just accept it and go and see Liz? Memories flashed through my head – all jumbled up on top of each other. My eyes wanted to close. I had to force myself to keep them open, not that I could see much as my vision was starting to become blurred. My body was telling my mind that it was suffering and didn’t want to go on. Why not just sit down and rest? I didn’t dare. How the hell would I get up again?

I was hungry. I had a raging thirst. I worked as hard as I could to generate saliva to keep my mouth moist but that was becoming more and more difficult.

It must have been around midday, judging from the height of the sun (thank God there had been no more mist) when the ground suddenly started to fall away. Below me was a wide valley stretching across to the beginnings of the ascent to the next ridge. It looked as if I had about five miles to cross and then a horrendous climb up the other side. Heather and rocks – desolation.

That was the lowest point of my ordeal. I very nearly gave in to it all. Bugger Bill Dewar, bugger Purdy. Just chuck it in. I risked sitting down for a minute or two on a rock and tried to pluck up the courage to carry on.

It was then that I saw the flash. It was only for a second and was far away towards the foothills of the next range. Then I saw it again. But this time it seemed to be further south. And then a third time, even further over to the right.

Suddenly I was alert. There must be a road down there even if I couldn’t see it. That could only have been the sun flashing off the windows of a moving vehicle. Immediately I had hope of rescue.

I sat there for another half hour, continually keeping my legs and arms moving gently so that they would not seize up.

Then I saw the same phenomenon again – something moving flashed twice.

I stood up, groaning at the pains all over my body but light-headed and more positive again. Come on, Bob. You’ve only got to make it down to that road and you’re safe.

“Down to that road” meant three or four miles of heather on blistered feet, picking my way around great chunks of granite and being careful not to find myself in a bog. I could see two areas of bog cotton between me and my target which would have to be circumvented, probably adding another mile onto my journey.

I made it, but God knows how. It took me three hours and when I got to the road I collapsed.

I crawled on hands and knees along the grass verge until I came to a black and white post – one of these posts which help a driver to know how deep the snow is in winter. I had absolutely no idea where I was. I could be in Ross-shire or Sutherland – anywhere in the vast landmass that makes up the Highlands.

I could at least lean against the post, sitting down facing the road. I stretched my legs out in a V in front of me. I had to pray that a vehicle of some sort would come along. I was prepared for a wait as this was a single-track road with passing places – not one which would be likely to have a lot of traffic.

I also had to hope that a driver would see me. I could wave but I certainly couldn’t get up from my sitting position. I wondered about actually lying in the road to stop a car but my brain was still agile enough to tell me that such an option would be dangerous. I was only about fifty yards from a bend and a car could easily come round so fast that they might not see me and stop in time.

All I could manage was to take out my handkerchief and tie it on to the remaining piece of string that I had and throw it out onto the middle of the road. It was white. A driver should see that, I figured.

Totally exhausted, both physically and mentally I prepared to wait. I managed to stay awake for about half an hour then I dozed off.

How long I lay there, dozing, I have no idea, but when I was awakened by a hand on my shoulder it was already heading towards dusk.

“Are you alright mate?” said a soft Highland voice. I opened my eyes to see a kindly and concerned weather-beaten face peering at me.

I tried to answer but could do no more than croak. I had had nothing to drink during my trek down off the mountain and my throat was completely dry. I could only just clutch at his hand and give him a beseeching look.

“Christ, you’re in a mess,” he said. “We’d better get you to some help.”

I could only nod. “Come on then, up you get. Let’s get you in the car.” I could do almost nothing myself. He managed to haul me to my feet and with my legs buckling under me he dragged me to the car. He lent me against the side while he opened the rear door, keeping a hold of me in case I toppled over. I fell any old way onto the back seat. He pushed my legs in after me and closed the door. He then got behind the wheel.

“There’s a hotel at the edge of the village about four miles down the road,” he said as he drove off. “I know Mrs MacDonald who owns it. She’ll take you in, I’m sure.”

I tried to thank him but could only manage a rough rasping noise.

When we arrived getting me out of the car proved more difficult than getting me in. “Hold on a minute,” he said. “I’ll be back.” True to his word he was back in a couple of minutes accompanied by a woman who turned out to be the aforesaid Mrs MacDonald.

She looked at me, at first with horror, and then with concern.

“Right, Jim, you take one arm and I’ll get the other. We’ve got to get this poor man inside.”

They manipulated me out of the car and lent me across the bonnet. Jim undid the strings around my ankles and did his best to get rid of all my insulation. I was vaguely aware of Mrs MacDonald undoing the front and the sleeve of my shirt for the same purpose. They then hiked me across to the front door of the hotel and inside, leaving scatterings of heather in my wake. Once inside, I was carefully lowered into an armchair in the reception area and they both stood back to look at me properly.

I hate to think what I looked like but Mrs MacDonald was up to the task. I made signs with my hands that what I needed desperately was something to drink. I was also shivering with the cold and the shock of my ordeal.

“Jim, there’s a blanket in that cupboard over there. You get it round him while I get him a cup of tea.”

I did manage to convert my rasping voice into a semblance of the word “whisky” which Jim immediately understood. He nipped into the bar and came back with the life-saving nectar and helped me to take a sip, before my cup of tea arrived.

“Take your time,” said Mrs MacDonald “Get your strength back. Whatever happened to you you’re safe now.”

I tried to smile but that was almost beyond me as well. “Can I leave him with you, Maggie?” asked Jim. “I need to be getting back. Or is there anything more I can do?”

“Don’t worry,” she said. “I’ll look after him. I’ve got no one here tonight and I’ll get the doctor to him in the morning.”

I tried to thank Jim by means of signs and he left. I continued to sit there taking alternate sips of whisky and tea until at last my mouth moistened up and I was more or less able to speak. During this time Maggie sat opposite me. I was now able to take her in properly. She looked about fifty. She had neat short black hair and a kind sympathetic face. Her nice comfortable-looking figure was clad in a tartan shirt and a pair of black trousers. Her whole demeanour radiated competence.

Her brown eyes smiled at me and I managed a halfhearted smile in return. I told her how sorry I was to put her to all this bother.

“It’s not a problem,” she said. “What you need is a bath and a good night’s sleep. We’ll phone the doctor tomorrow. Do you want anything to eat?”