"This is the way the world ends/Not with a bang, but a whimper." - T S Eliot

The world ended.

I don't know if you ever think about it. The world ending, I mean. I know I didn't. Not really. I had a job, I had somewhere to live, I knew how the world worked.

I guess that I always expected that if the world was going to end, it would be pretty spectacular, and everyone would notice immediately. Big things would blow up, or aliens would invade and we'd all die.

I kind of figured perhaps we'd just suddenly turn on the TV and the news announcer would say "Sorry about this, folks, but in exactly twenty minutes the world is going to end and we're all going to die." And it'd be scary and terrible and unexpected, but at least it'd be quick.

But it wasn't like that at all.

My name is Alisa, and I'm twenty-six years old next March. I used to work as a cleaner at the bank, and I wasn't anybody important at all. I liked it that way. Being unimportant meant you didn't get spied on by the Ear or have your family disappear overnight when the Fingermen came by. But now there's no Ear, no Finger, and I'm one of the most important people in the whole world.

I survived. Me and the others: Jake, Brandon, Rowena, Sally - and Guy. There aren't many of us, so we're precious and rare. We survived the end of the world.

For a while, I thought I was the only one.

The world didn't end quickly in a big explosion, like I was saying. It happened quite slowly, at first. I went to work on the Tuesday morning, an ordinary Tuesday with my uniform on and my permit in my hand. The bank was one of the big buildings near the wharf, you couldn't miss it. Every morning a stream of people filing in, like ants, and at the end of the day the same. Like clockwork. Reliable. I liked it. I had to be there before the nine to five crowd arrived, to empty the wastebaskets and vacuum the floors. Like I said, I was one of the invisible people and glad of it. We had a little room in the basement where we could sit and watch the TV, us invisible people, and that's where we saw it start. Gloria and I: Gloria died, I guess, because I never saw her again after the Thursday. She had a great smile and one gold tooth. That's all I really remember about her now.

The Thames began to rise. There were pictures of the water, and an official from the Nose standing up to his ankles in it, holding a measuring stick. He was smiling, and people were laughing at him with his trousers rolled up, because it's so rare to see someone in authority acting like that. He was telling us not to worry, that it was just a late autumn tide, that it would be going down again in a day or so.

So we didn't worry. The Government knew what they were doing. It's their job, right? I went home, spoilt myself by splashing out an extra coupon on water for a bath, then got up in the morning and didn't even realise anything was wrong until I wasn't allowed to get on my usual bus to work. The streets, the driver said, were flooded. We'd have to go the long way round and come up the wharf from the south side. We all did what we were told because it was the only way we knew.

My jeans were soaked by the time I walked into our little basement room. Gloria was late that day: and when she arrived she was wet through and her hair was stuck flat to her head with water. The rain, she said, was coming down in sheets.

The TV said the same: the announcers made some jokes about ducks and swimming pools but still told us not to worry, that everything was being taken care of. I often wonder if any of the people who were already dying at this point heard the jokes. Whether it was the last thing they heard, even. I really hope they didn't. But then nobody knew people were dying except the ones who were doing it, and word didn't get out. No word got out except the words the chancellor wanted you to hear. Guy told me a lot of this later, once he started to talk again. Guy's a clever man, but more about him once I've got through the hard bit.

On Thursday, it was all over.

I guess it'll probably take years for anyone to work out the reason for what happened. Global warming. Freak storms. Act of god. Does it even matter? I didn't even finish geography at school, I wouldn't understand it if someone tried to explain. For me, it just happened. Knowing why wouldn't make it any better or solve anything.

The waters rose from below and hammered down from above harder than I could ever have imagined. There had never been rains like that before, so there was no way anyone could have guessed what it would be like. What it could do.

I went to bed after curfew, as always, and when I next woke up I was the only one alive.

I'd like to say that moment of waking up was the most terrifying possible, but I've experienced a lot more terror since. I woke up when my building was destroyed. I can't describe it properly, because it was everything at once: the cacophony of screams, of concrete and brick crumbling, the building smashed to pieces in less time that it takes to blink. The chill and stink of the water - no slow rise, just a sudden plunge, the water rising up from below to engulf through the floor as the windows imploded in sodden showers of glass. The brick and stone sank, and I floated, in that watery limbo, not knowing what had happened.

There wasn't even time for pain, and it was just before dawn, so it was dark and through the abrupt murk of the water I couldn't see. Things I couldn't begin to guess at smashed past my legs, my arms, my head. I was probably bleeding. But none of these things matter when you're underwater: only one thing is important, and that's that there is no air. I couldn't breathe. Instinct took over, and my body moved for light, for surface.

I found it. Millions didn't. I don't know how. I wish I could say I felt what they call survivor's guilt - why me, instead of hundreds of others, people who might have been more worthy, more useful? But I don't. I'm glad to be alive, and proud that I managed to find a new home with the only others that survived. Maybe that makes me a bad person, I don't know. But if you're reading this, then you survived too, so I guess you know what I mean.

There's not a lot I can say about the few days that followed. I'm not the right person to tell it, either. It's too big for me. Maybe, if he chooses, Guy could manage it, one day, but I just don't have the skill or the words. What I can say is that the water did recede, and what remained of London emerged slowly from under the new seas. And I, alive and cold, came out to meet it. There were silt beaches in the Strand: I know, I walked along them. Little rivulets of water sparkled between the piles of rubble and smooth expanses of mud. It reminded me of older days when my parents took me to the beach at Anglesea. There were fish, in the little pools, swimming amongst stranded tins and boxes, chairs and cars. I suppose I thought, on those first days, that I was alone in an alien landscape and that there was no-one left in the whole world to see it except me. It all looked very new, and flat, and strange. Every so often I'd find something that I thought I recognised, but the truth is there wasn't anything to recognise, not anymore. It was all gone. Only the birds were still there, gulls and sparrows landing and pecking in the mud. There weren't even as many bodies as I'd feared - I found out later that the water had carried most of them back out when it retreated. It was an empty world, and I was very frightened. Like I said, I'm not a big-picture sort of person, but even I could see that there wasn't any Government anymore. No High Chancellor. Everything had changed overnight and everything I'd grown up believing was gone. No-one in charge, no-one to set a curfew or make the rules or tell us what to do through the TV. And of course the only part of the whole situation (which my own personal fear laid claim to) was that no-one in charge meant no-one to rescue me.

On the third day, I found my first real set of bodies, and Brandon found me.

There wasn't anything dramatic about it. He just called out "Hey! Hey, you!" in the most cheerful voice imaginable, while I was staring in mute horror at the cluster of corpses I'd just discovered inside an upturned skip on the silt flats of Trafalgar. Brandon used to be an accountant for the Nose, not that it matters now when he spends most of his time digging and draining. He has red hair that sticks up in a bright thatch, and glasses, thick glasses that never stay up on his nose. Later I realized that the glasses never stayed up because they weren't his. He'd lost his own when the world ended and had to make do with the best ones he could find.

"Hey, you're alive!" he beamed at me, as he stumbled down the bank of broken furniture, splinters of wood the length of his arm scuttering away from his feet. I watched him numbly, not sure how to react. What's the etiquette for greeting a newcomer when you thought yourself the last human alive? Fortunately, my body knew what to do. It crumpled into his arms, and cried, while Brandon patted and cuddled. He smelt like sunshine, where his wet clothes had dried on him.

His wife and family had been killed, or so he thought, he told me as we walked on through the mud. He didn't know for sure, but seeing as everyone else was dead it was a likely guess. He didn't seem to be grieving very much, with his flickering smiles and kindly words. It was only much later, on that memorable day when we all crouched together in the cornfield in the rain that I saw him cry for them.

And it was with Brandon, when we went out later to see what food we could find on the new salt flats, that I first met -

"Hey," Brandon had said, tapping me on the arm. "Look at that."

We thought he was dead, at first. He was lying in the mud, half-covered with a big spill of black cloth that I thought was blanket but turned out to be a cloak, when we got closer. I hadn't even wanted to go - I hated the bodies, tried to do all I could to keep away from their sad, decaying forms - but Brandon was intrigued and pulled me along with his curiosity.

And this body was intriguing, no denying it. For a start, he was wearing a mask.