There are a lot of coughs and sneezes going around the jail at the moment. It is always the same at this time of year. No matter how hard you try to guard against a contagion - vitamin C supplements, cod liver oil, hot water bottles - we live so close to one another that when one person goes down with something everyone ends up with it eventually.

So far I have been lucky this year. Not spending so much time in the place has helped I suppose. I do not need to cram myself into the back of the prison van twice a day either, now I have the car. But that only gets me as far as the station. I still have to sit in a packed train carriage for the best part of an hour each weekday morning and evening. I don't mind that, except too often it leaves you exposed to the seasonal bugs of others.

Only a couple of evenings ago I found myself sitting next to a demonic sneezer who had obviously set off for work ill-prepared for a virus manifestation. Without a hanky or tissues, or even toilet paper - which serves perfectly well in an emergency - the man was left with only his hands with which to prevent the sharing of his contaminated mucus spray with those jammed tightly around him. They came in threes, his sneezes. With all seats taken and the aisles choc-a-bloc with upright bodies there was no hiding place.

As a protective measure, each time the sneezer began his build-up, the woman opposite and me held our broadsheet newspapers up high and close to our faces. The man sitting next to the woman, who faced our germ-laden travel mate, did his best to do the same with a tabloid freesheet. Haaarghtchoo! Haaarghtchoo! Haaarghtchoo! Three emphatic eruptions. Sympathetic exclamations of "Bless you" were conspicuous by their absence. I was sure my epiglottis was going to tingle in the morning (usually the first sign of an infection) but so far so good.

In case anybody was wondering, being ill in jail is no fun at all. If you can persuade the prison doctor that you are a genuine case you might get a few days "sick in cell". But don't expect hours of uninterrupted recuperative rest. Just as you are nodding off an hour or so after breakfast, the cell door will be flung open and in will march a couple of prison officers on daily "locks, bolts and bars" duty. They will hammer the window bars with a baton - to make sure you haven't been sawing through them in the night - and "test" the bolt on the door by rattling it back and forth violently several times. Locks will be tested with five or six robust turns of the key, with maybe a kick or two of the wide open door thrown in for good measure. You can try to ignore the intrusion by hiding your head under the covers if you like, but it will be difficult with the officers demanding sceptically, "What's up with you then?"

Once they have gone you will have landing cleaners banging on your door all day asking, "What are you doing in there?" or, "Have you got a Rizla?" If you want to eat, when your cell door is opened at lunchtime and again at teatime you will have to get up and join the queue at the servery - or risk an irate servery officer appearing at your doorway with his clipboard to inquire, "Not eating then?" If you really are poorly, going sick in cell is unlikely to give you much of a respite, though the upside is that once the day is over you could be so exhausted that you can't help but fall into a good night's slumber.

Prison can do strange things to a person. A fellow convict who once occupied a cell near me used to trade most of his prison wages for cheese stolen from the kitchens. Just before bedtime he woud eat the cheese in big lumps in order to induce nightmares. Even by prison standards this was odd behaviour. When I eventually asked him why he did this, he said, "So that when I wake up, being in here doesn't seem so bad." A fine example of twisted logic.

I am a bit like that when it comes to illnesses. Since being in prison I have not minded the occasional bout of something viral (and prison viruses are famously monstrous.) Feeling so wretched that just the flicker of an eyelid fires daggers of pain from the scalp to the toenails, tubes clog and tear ducts stream, joints ache and lips crack, is a great way of being reminded of how wonderful it is, even in unfavourable circumstances, to normally enjoy good health. So many people don't.

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