The operator on the swine flu hotline needs to know if I have a fever. No fever, no swine flu. So I venture out to buy a thermometer. The pharmacy at the corner has run out. I drag myself to the next chemist on the high street, but the shelf is empty: the last digital one sold yesterday. Nearby is a Superdrug. Sweating and coughing, I run through the store looking for thermometers. None.

I call Superdrug. They say sales of thermometers have doubled each week for the last three weeks. Lloyds pharmacy has sold 700% more thermometers than for the same period last year.

Even thermometer suppliers are getting nervous. Andrew Brannan, of Brannan thermometers, says it was the same with Sars. "We couldn't keep up." So how did it end? Did we all find a long-lost one in the bathroom? "No," he says. "The story disappeared and the demand stopped."

I finally found a chemist that had some stock. I don't have swine flu, but I will keep this new thermometer tucked away for the next crisis.