By five o'clock I had made reasonable progress towards reaching Samantha. With only a few days of the month of October remaining, the light had almost entirely faded by that time and the disappearance of the sun offered some respite from the conditions. While the heat seemed not to have reduced by even the slightest fraction of a degree, the advent of darkness brought welcome relief to my tired eyes. I wondered if the brightness might be doing some serious damage to my sight but then I realised that it mattered little - if the world continued along its path to destruction, the chances were that I would be dead before I went blind. I tried not to think like that, but could not help admiring the irony of it all.

While I walked, there was little else to do but think as I had seen no-one to speak to since leaving the tramp in the toilets earlier that afternoon. Although I tried hard to stop them, it was difficult to prevent frightening, gnawing questions from materialising in my tired imagination and, while I did my best to try and ignore them, it was almost impossible to stop myself from searching for answers. Nagging doubts began to form in my mind as I wondered if Samantha really wanted me with her or if she would prefer to be alone with her family. The more I thought about her, the more I managed to irrationally convince myself that Sam didn't need me as much as I needed her and that, perhaps, I had been nothing more than a convenient shoulder to lean on and to cry on in the city. However, I remembered our time together with fondness and my memories of making love with her in the hot night air helped restore some of my faith in our relationship.

As well as feeling pathetically miserable and alone, I also felt an incredible and inescapable guilt at not having made the effort to go straight to my family. Although I tried to convince myself that I would carry on to them once I had reached Samantha, I knew in heart that there would not be enough time. And if Samantha didn't want to be with me when I got to her; what would I do then? I knew that there was little point in worrying - according to the voices I had heard on the radio last night there was not much time left. At least if I was to be alone, I would not be lonely for very long.

I had consciously followed a sensible route all afternoon which led along country lanes and roads and which only left the beaten track on the rare occasions when there was no real alternative but to trample across a dry and dusty field or over a barren, exposed hillside. The route was virtually a direct line to Samantha and I only needed to make a couple of minor alterations to miss dangerous and avoidable obstructions such as small towns and villages. The traffic levels had fallen throughout the morning and since the energy pulse had struck I had seen no cars moving at all. There had been, however, plenty sat still, frozen and abandoned at the sides of silent roads. It was now safe to walk along the middle of what had been even the busiest roads and, at half past five, I found myself trundling down a steep slip road which led onto a motorway strewn with the dead shells of cars but devoid of people and movement.

The concrete and tarmac of the carriageway was still warm and occasionally sticky under the soles of my rapidly wearing trainers. By that point I had made the painfully obvious connection with the striking of the energy pulse and the death of all the cars and I presumed that the power of the wave had been such that it had irreparably damaged all electrical circuits. It was worrying to try and imagine what the effects of the next pulse might be if it increased in strength and power again as the last one had. The only benefit I could see in the sudden lack of transport was that there was now a good chance that Samantha would stay at her grandmother's house and wait for me there. I dared not think about how I would feel if I struggled all the way to Colliwell only to find that Sam had turned around and gone back towards the city to look for me.

There was a faint light in the distance and I squinted into the darkness ahead to try and see where it was coming from. As I approached the source of the light, I saw that its dull, yellow glow came from underneath the bonnet of a family-sized saloon car which had stopped in the fast lane of the opposite carriageway of the motorway. As I neared and made my way across the central reservation, I saw that the light came from a little gas-powered camping lantern and that someone was working on the engine of the car in a desperate attempt to try and get the vehicle restarted. The sound of my shuffling footsteps on the dry ground disturbed the body under the bonnet and a chubby, middle-aged man lifted himself up to face me. He wiped his sweat-covered forehead and squinted into the darkness with his deep-set, piggy eyes.

'Don't suppose you know anything about cars, do you?' he asked as he dried his wet hands on the back of his grease-stained, cotton trousers. I walked over to the car and looked down at the idle engine.

'Not really,' I said, truthfully. I had not spoken for hours and my voice sounded dry, hoarse and tired. I cleared my throat before speaking again. 'I know how to put petrol in and how to change a tyre if I'm really pushed, but other than that...'

My voice trailed away into silence as I realised that the man was staring at me. The look on his face was identical to the expression of disgust that I had shown to the tramp in the toilets at the service station and I looked down at myself in the dull glow of the little lamp. The afternoon had taken its toll on my appearance and I had stripped down until I wore only a soggy, sweat-soaked T-shirt and loose, baggy trousers. On my feet, my trainers were battered and worn and the big toe of my left foot had started to poke out where the sole had begun to separate from the rest of the shoe. For some reason, almost instinctively, I apologised.

'I'm sorry I look like this,' I said. 'I've been walking all afternoon.'

The man turned away from me and returned his full attention to the car once more. It was obvious from his manner that, if I could not help him, then he did not want to be bothered with me. I took a couple of steps back away from the car and leant on my umbrella for support. Since sunset I had been using it as a makeshift walking stick which had taken some of the strain off my weary feet.

'Bloody thing's dead,' he snapped and he threw a greasy, oil-covered rag down to the ground in anger and frustration. 'I've got to get this lot to her sister's before tomorrow lunchtime and we've been stuck here since half-twelve.'

The man nodded his head towards the interior of the car and I peered around the open bonnet to see a pretty young woman sat in the passenger seat. She smiled at me politely but I could tell from her expression that she too was unsure of my ragged appearance. From the back of the car came constant sounds of moaning and fighting and I was just able to make out a little boy and girl squabbling over an exhausted Yorkshire terrier dog who panted in the suffocating heat as his fur was pulled in all directions. The occupants of the back seat did not even notice me watching and I returned my attention to the man under the bonnet. I decided to risk my theory concerning the pulse's effects on him.

'I don't think you're going to get it started,' I said, taking care to lower my voice so that I did not alarm the passengers in the car. 'I think that the heat and light earlier must have done something to knock all the circuits out. My car died on me as well.'

The man shook his head. He seemed ignorant and uninterested but I was sure that he too must have noticed that all of the cars had suddenly stopped. I looked quickly around and it became obvious that, from where we stood, no other cars could be seen.

'You're talking rubbish, lad. That light was bloody hours ago. Besides, how could that have done any harm?'

I shrugged my shoulders as I was unable to offer any scientific proof or explanation to support my theory. He was right - it could easily have just been coincidence.

'No' he continued, 'it's got to be something simple, something obvious. It's bound to be staring me in the face.'

The only thing that was obvious to me was the fact that the man I was speaking to was a fool. Against my better judgment, and for no other reason than the fact that I had been alone all day, I tried once more to convince him of my theory.

'I've heard about something similar to this happening after nuclear explosions. I think it's called an EMP effect. Electromagnetic something or other.'

The man laughed.

'I think you're talking crap, son,' he said, chuckling to himself. 'The only thing the heat and light's done is scramble your brain!'

'Think about it,' I protested, ignorant to the pointlessness of my efforts. 'Have you seen any other cars moving since the energy pulse?'

The man shook his head with mirth and continued to tinker with the engine of his car. He laughed and muttered to himself as he worked. I was quickly becoming annoyed.

'Fuck you then,' I said bluntly and I walked quickly away, crossing back over what remained of the central reservation. I glanced over my shoulder and saw that the man was watching and laughing at me. Perhaps he would listen when his family started to weaken and die, I thought, but by then it would be too late.

As I walked away, I wondered if the man would ever get the car going and, if he did, would it have been worth all of the effort? Where would he take his family to? Nowhere would be safe if the end did come as predicted and it wouldn't matter if he was driving along at ninety miles an hour or walking along the side of the road - when it finally arrived there would be no escape from the heat and light.

By my rough calculations, at my present slow speed, Samantha was still the best part of half a day's travel away from me. I tried to visualise the distance that I had travelled so far and imagined how long it would take me to get home if I decided to give up and turn around. No matter how hard I tried, I could not think of a situation when I would even consider doing that. I took the battered and crumpled map out from my trouser pocket and, as I took a long drink from one of the remaining bottles of water, I verified the distance that remained ahead of me.

It would be ironic, I thought, if things did return to some kind of normality. I knew that the world would now never get completely back to normal and I dared not even imagine what kind of madness would be waiting for me should I ever be forced to return to the office.

As I walked, I thought about some of the friends that I had left behind when I had escaped from the city. I wondered how Rebecca was and if she was safe at home. I imagined Mark with his university friends drinking themselves senseless to avoid the coming storm and I hoped that neither of them were wasting precious moments thinking about me. In the little time that was left, I wanted them to be concentrating on their own lives and on making themselves as comfortable as possible in the time which remained until the end arrived.

Thinking about my friends depressed me further still. Everybody else that I knew would be close to the ones that they loved and held dear to their hearts. I imagined that I was the only person on the face of the scorched planet who felt so alone.

Time dragged slowly on and, even at midnight, the temperature was such that it was difficult to keep walking. I hoped that the planet would be able to survive long enough to allow me to reach Samantha as I could not bear the thought of dying alone without her. I had quickly got used to the fact that I might not live for much longer and had accepted my painful and inevitable destiny. What I couldn't bare to face was dying alone.

I wished that I could have met Sam at another time. If we'd met before all of this had happened then we could have forged an incredible life together. I knew that if I had known her for longer then I would not have been here alone, tramping across the starved, empty countryside in the middle of the night.