Single File: A man in work asks me: "Are you like this at home?" To which I reply: "Yes, I am often like this at home" - "this" meaning ragged and a little unhinged. "But it doesn't matter because I live alone."

At home I can have all the mood swings I want. And I do. But I am no Shirley Valentine. When I talk to the walls they ask me to stop. I can't blame them. When I talk to myself I ask me to stop too.

When I say I live alone, I lie. I live with television, radio, traffic and cardboard cut-outs. At night there are invisible (street) fighting people.

I also live with a small winged thing called Fly, although he comes and goes. Sometimes my family meets up, and my mother and siblings chat about the birds that visit their gardens. I tell them about the fly.

In work they talk about the sun and how it hits the back of their houses, and where they sit in their gardens when the sun moves. Being gardenless, I tell them about the fly.

This probably makes more sense if you twist a cliche to say: company is in the eye of the beholder.

The fly is company, but only just. He does not make tea or fight over the telly or report on his day. He does not give fashion advice or share his food or fetch medicine when I'm ill. He never has cash for loans.

On the plus side, I can treat the fly how I like. Before I kill him he does not even seem to notice. Most importantly, he understands that there is such a thing as too much peace and quiet. And he acts on it: "Buzz, buzz."

The fly's buzzing is his way of telling me that I'm not alone. He is like a radio without the off button. But sometimes it is a pitiless nagging, like the worst qualities of all my ex-flatmates rolled into one.

Once, during a rare stint of positive thinking, I resolved to see the fly as the symbol of my creativity - the untapped and unfettered parts.

Not long after that I gave up and decided to kill him instead.

Living alone, you occasionally wonder where your back-up is. After scouring the flat for support - cobwebs but no spider - I went at him with a rolled up newspaper.

Success. Then bliss, because there is no silence like post-fly death silence.

But it does not last.

I don't believe in reincarnation, and anyway it seems unlikely a fly would come back as a fly - in the same way that it seems unlikely a civil servant would come back as a civil servant - but the next fly looked very like the first one.

And on it goes.

People say that if you live alone you need a routine. Lately I seem to spend my nights in, killing a fly.

There are support groups for people who live on their own. One of them is called Television. I watch the same episode of ER twice in one week. The characters smile knowingly. "There you are again," they say.

The other support group I belong to is called Friends - the real-life version.

But it seems to me that living alone can lead to unrealistic expectations of human company. I meet up with my friends and expect them to listen to me, even if I am only talking about ER or the fly.

I shouldn't be surprised when they don't listen - even my new therapist isn't listening to me.

Last week he asked me if I have an answering machine, and whether it would cause embarrassment if he left a message on it. I said: "No, I live alone, remember? And I already know I'm in therapy."

Anyway, I finally gave in and bought a fly-zapping machine. There are no flies to talk about now. Instead I go to the park and study the birds there. I take pictures and show them at family outings - "here I am with two fat pigeons", and "here I am with three fat pigeons".

If I angle the camera carefully, it almost looks like I might be in a garden.

Next week: a superhero for people on their own