When we bought the house, we didn't know that it had a fallout shelter. The estate agent's flyer mentioned all the usual things: kitchen, dining room, original features - all the things that you would expect to see. But there was no mention of a fallout shelter. The house had been built during the 1950s, at the height of Cold War paranoia, so maybe we shouldn't have been that surprised. According to our new neighbours, the previous owner - who had owned the place from new - had been something of a stranger. But we hadn't been able to confirm that for ourselves. We had bought the house as part of an estate sale, complete with all its fixtures and fittings. So, when we found the fallout shelter, we were quite surprised.

The entrance to the shelter was through a trapdoor in the floor of the cupboard under the stairs. It was concealed beneath a pile of junk that seemed to have been there forever. My wife found it first, as she was cleaning out the cupboard. "I didn't know we had a cellar," she said.

I put down the box I was carrying and went to see what she had found. There, set into the bare, concrete floor, was a metal hatch. "Nor did I," I replied.

Together we hauled the hatch open., swinging it up on rusty hinges. Beneath the hatch was a deep shaft with a ladder on one side, leading downwards.

"Looks dark," my wife said.

"I'll get the torches."

My wife was the first one down the shaft. I stayed at the top, shining my torch onto the rungs of the ladder as best I could. She went down about fifteen feet, then stopped. "Hey!"

"What?" I called back.

"There's a door down here. I'm going to take a look."

"Hang on!" I began. There was the sound of metal scraping against concrete, and my wife vanished from sight. I waited a minute. "Are you alright?"

Her breathless reply drifted up the shaft. "You have to see this."

I stuck my torch into my belt and climbed down the ladder to see what she had found. At the bottom of the shaft was a small, boxlike room with two thick, metal doors. Beyond it was ... "Wow!"

"Definitely 'wow'," my wife said.

Just inside the second door was a large, concrete-lined space, easily as big as any room in the house above. Utilitarian metal shelves had been bolted to the walls: each one filled with tins, bottles and boxes with faded labels. Old furniture - two bunk bed frames, a table and a handful of chairs - had been neatly positioned around the room. Another door promised access to more.

"What is this place?" I asked as I swung the beam of my torch around the room.

My wife picked up a couple of brittle-paged pamphlets from a counter top. She looked at them for a moment before holding them up for me to see. I could make out images of mushroom-shaped clouds and various logos. "I think it's an old shelter," she said.

"Great." I began to laugh. "More junk to get rid of."

The fallout shelter did have a lot of stuff in it. There was food and water, but this had long since passed its expiry date. There was some bedding and household supplies as well, but these were too old to be useful. What there was, was a goldmine of old books, board games and manuals - "They should be worth a bit to some collector," I remarked - and, best of all, a vintage AM radio. I opened up the back to check if it was still in working order. The bakelite casing was in good condition, and the wiring and valves seemed to be intact; but the batteries had split and were covered in white crystals.

My wife held up a greasy cardboard box. "I've got some spares here." She used a screwdriver to prise the old batteries from the radio, replacing them with a fresh set from the box. That done, she fiddled with the knobs on the front of the radio. The tuning dial lit up, and there was a loud burst of static from its speaker. "Looks like it still works," she said.

We tried different frequencies to see if we could pick anything up. There was nothing but static. "I guess the shelter must be blocking it," my wife said. "Let's take it upstairs and try it later."

I nodded in agreement. "Later. We've got to clear this place out first."

It took a while to clean out the fallout shelter. The radio went on a shelf in the pantry, where we forgot about it as we got on with the rest of the chores in our new home. It stayed there until - CRASH!

I was working in the lounge when I heard the sound of things hitting the kitchen floor and my wife bellowing in frustration. I came running into the kitchen to see what had happened, and found my wife standing in front of a collapsed shelf. She pointed at the mess on the floor between us. "It just fell," she said by way of explanation.

"It just fell?" I began to pick up the pieces of broken crockery and fragments of glass that littered the pantry floor.

"Do you think I did this deliberately?" My wife picked up the old radio that we had brought up from the shelter beneath our house. "Hey!" she said. "It's working."

She put the radio on the kitchen table, and I went over to take a look. The tuning dial was lit up from within and there was a crackling noise from the speaker. "Let's see if we can pick up anything now," I said, and slowly spun the tuner through the frequencies. The crackling turned to a barely audible hum, before turning into a low-pitched whistle.

My wife leaned in close to the speaker grille. "That's more than we got before."

"Quiet. I think there's something about here." I turned the dial a few degrees further on and was rewarded with what sounded like a voice.

"Turn it up. I can't hear."

I adjusted another knob, and the voice became louder: "... Days since the last bombs. We're trapped in here, and our air is running out."

My wife and I looked at each other. "What?" I began.

"I don't know. Maybe it's some kind of a play? Do they still do those on the radio?"

"Sure. It's not all pop tunes and sport."

We continued to listen to the voice on the radio. There was just one voice - that of a young man. He sounded tired, as if he had endured some great torment that had scarred him, but who knew that his ordeal would soon be over. The monologue continued for another ten minutes, with the voice becoming more breathless, more resigned to whatever fate had been ordained for him. His last words were, "That's it. No more." Then there was silence, apart from the hum of the carrier wave.

"Wow," my wife said. "That was intense."

"It was. I wonder who wrote it."

"The credits - they'll tell us."

We turned our attention back to the radio, but we were never going to find out. The light had gone from the radio's dial and the speaker had gone silent. I tried to coax the radio back to life, but with no luck. "Damn."

My wife put her arm around me. "Never mind. We can look it up on the internet."

We left the radio where it was and didn't give it another thought until two days later. We were sitting at the kitchen table, eating a quiet supper, when the radio came back to life. At first there was only a quiet hiss that made us wonder what was going on. Then there was a burst of static and a voice started speaking. It was the same person as before, only their voice sounded stronger.

"... Still here. We're still here. I know things are looking bad, but we're not going to desert you. Not while we can still broadcast."

"Did you touch it?" I asked my wife.

She shook her head. "No. I've been right here. You know I have."

We stared at the radio in disbelief, listening to the voice. The speaker would stop to cough, his lungs rattling with the effort. Although he was trying to sound hopeful and optimistic, there was an undercurrent of despair and resignation to his words. Then, just as suddenly as it had started, the transmission ceased. The radio was dead again, as were our appetites. We scraped the congealed remains of our dinner into the bin.

After that, my wife wanted nothing to do with the radio. She insisted that I throw it away, get rid of it. "Whatever! Get it out of my house!" But I didn't want to get rid of the radio; at least not until I had found somewhere for it to go. So, I put the radio into the cupboard under the stairs, the one where the hidden entrance to the fallout shelter was. As I was the only one who went in there, I was sure that my wife wouldn't notice. But she did when the radio turned itself on again.

This time it was after midnight. We were in bed, asleep in each other's embrace. Our dreams were shattered by a piercing tone that seemed to fill the room - the whole house! To our sleep-addled senses it felt more like an intense wave of pressure than a sound. I sat up, looking around in panic as I tried to work out where the noise was coming from. My wife was holding her head, crying, "Make it stop! Make it stop!" I threw the bedclothes off me and stampeded down the stairs.

Before I was halfway down, the sound stopped. There was a brief silence, followed by three bangs and a voice - the voice from the radio - began to speak. "Fallout warning red! Fallout warning red! Attention all areas!"

The radio! Of course! I flung open the cupboard door as the voice began to recite a list of places and numbers. In the semi-darkness I could see the red glare of the radio's innards, glowing like the embers of a dying fire.

My wife clattered down the stairs, almost knocking me over in her hurry. She grabbed me. "I told you to get rid of it."

I said nothing.

"What's it doing in there?"

I didn't respond. Instead I stood there, listening to the voice as it announced expected radiation levels and maximum exposure times.

"Get it out of here! Now!"

Her hand caught me across my face, bringing me out of my stupor. "It won't stop," I said. "Not until it wants to!"

"I don't care. Get rid of it. I don't want it - or you - in the house. Don't come back until you've thrown it out. Go!"

My wife turned away from me and stamped back up the stairs, leaving me alone with the radio. I picked it up and wrapped it in my t-shirt, hoping that would be enough to muffle the voice. Then I carried the radio into the kitchen. I could feel the warmth from its bakelite shell. The voice was starting to fade. There was a last, quiet, "Good luck", and then the radio went dead once again. I put it down on the kitchen table and pulled up a chair. I was tired. I needed to rest. I didn't remember falling asleep.

The morning sun woke me. I yawned and stretched, enjoying the feeling of the warm light on my body. For a moment I wondered why I was in the kitchen rather than upstairs in my bed. Then I remembered why. I pulled my t-shirt off the radio.

"You've got to go," I told the radio. "My wife doesn't want you here. And if you're going to be any more trouble, I can't say that I disagree with her. As soon as the recycling centre opens, I'm taking you there and leaving you."

I reached out to pick up the radio; but, as soon as my hand touched it, its tuning dial began to glow. "Attention!" the voice said. "Attention! This is the Wartime Emergency Broadcasting System, transmitting on the AM, FM and long-wave bands. Attack warning red. Attack warning red. As of 1200 GMT on ... ." I stopped. The date the announcer had just given was today! Noon was only - I checked the clock above the kitchen door - not even five hours away!

The voice on the radio continued. "Enemy missiles have been launched, and are believed to be targeted at all major population centres. Initial casualty estimates are high."

I hurried upstairs to find my wife, to tell her. But all the time I was thinking, "We only just cleaned out the fallout shelter. Now we'll have to put everything back."