AT BREAKFAST one morning last week my husband put forward the following hypothesis: the reason he has had so many colds this year is that he keeps losing his scarf, writes Lucy Kellaway

I told him not to speak in this way in front of the children; the thought that their malleable minds should be exposed to such unscientific tosh was painful to me. It is a proven fact, I said, that one does not get a cold because one is not wearing a scarf. It is a proven fact, he replied, that one does.

In the office I scornfully retold his theory to a well-educated, sensible colleague, who - much to my dismay - solemnly agreed with my husband. Within seconds our disagreement escalated and she and I were staring at each other with the same sort of hostility I had witnessed the previous day between two journalists who had been debating Israeli attacks on Gaza.

The common cold might be common but it attracts an uncommon amount of feeling. Last week in the UK the controversial topic made it on to the televised national news because the makers of Benylin cough mixture had come up with an ad in which a nice-looking woman wakes up one morning with a cold. She struggles to get up, but the voice-over urges her to stay in bed and "Take A Benylin Day". We then see her propped up in bed happily reading a book.

The Federation of Small Business (FSB) then lodged a complaint, saying that people should not be encouraged to stay at home with a cold. One can understand their point of view. According to the Sun newspaper (not the most reliable source, but still) 2.4 million Britons threw a sickie last Monday.

If any more were encouraged to take to their beds just because they have a sniffle there would be no one presenting themselves for work at all.

So what is the answer? Should you stay at home if you've got a cold? Clearly, it all depends on how bad you are.

As a child, if I woke up in the morning with a runny nose, I had my temperature taken. I then waited for a tense 30 seconds willing the mercury to rise above 98.6°F. If it did, I was allowed to stay in bed. If not, I was given an aspirin or Lemsip and packed off to school.

This approach was good because it encouraged backbone. It discouraged self-indulgence, and it allowed one to distinguish between minor ailments, which are a nuisance but better not dwelt on unduly, and major ones, which are something else entirely.

An inability to distinguish between the two is common particularly among men. When I stumble upon someone who calls a cold "flu", or makes a huge fuss about having one, it causes me to shift ever so slightly what I think of them, in much the same way as Maggie Thatcher's view of Alan Clark, the Conservative politician, shifted when she found out he was a vegetarian.

The cold doves - who have been writing passionate columns in serious newspapers decrying the cold hawks at the FSB - argue that people with colds should stay home as they are no use at work and turning up just makes them worse. This isn't my experience. A cold runs its natural course, and going to work gives you something else to think about while you blow your nose. A slightly less feeble argument is that people with colds should stay at home or else they will infect others.

Colds, as we all know, are very infectious. If you are cooped up in an office with someone who is coughing and sneezing then you may get a cold too. The germs leave their nose, and end up in yours. It is all most unfortunate.

Even this I don't entirely agree with. We are all exposed to cold germs all the time, so the question should not be how to stop the exposure but how to make oneself less likely to succumb.

One way, recommended by doctors, is to wash your hands as often as Lady Macbeth and to refrain from sticking your fingers into your nose. Another way, recommended by the Japanese, is to make everyone wear a mask. This is a good idea, but has the drawback of making the office feel like a surreal nightmare in which all your colleagues have become dentists. better way of not getting a cold is to enjoy one's job and feel valued in it. It seems to me that people who like their jobs and feel indispensable succumb to fewer colds than those who don't. People tend not to get bad colds when they can't afford to; those in happy jobs tend to get colds at the weekend and on holiday.

I should admit that my evidence for this is more anecdotal than scientific, though I did find some research in the Lancet saying that people with depression were more susceptible to colds than those without, which seemed to amount to the same thing.

Which leads me to my own theory about colds and why they have been so bad this year. It has nothing to do with scarves or the cold weather. On this score, I direct my husband to Wikipedia. I realise it is fashionable to be sniffy about Wikipedia, but on colds it is surely sound in stating categorically that you do not get them from being cold.

My theory is that colds are bad this year because of the recession, which lowers our spirits and makes us feel dispensable at work. In this state, our bodies are subconsciously waving and beckoning to any cold virus going, saying: over here. This explains why more than 8 per cent of the UK workforce was off sick last Monday: the economy has sneezed, and we have all caught a cold. - (Financial Times service)