I nearly became a weather forecaster once, but unfortunately I was too good for the job.

It happened like this.

I had seen an advertisement in the paper which said: “Ladies and gentlemen invited to apply for the post of TV weatherperson. Preferably should have interesting physical defect or slight speech peculiarity, and should be able to point accurately at map without looking at it. Successful applicants will do weather forecasting for several years and then go on to a full-time career in after-dinner speaking as a much-loved British personality."

It sounded ideal. There was no mention of any knowledge of meteorology, which suited me fine, as it was the one weak link in my suitability as a weather forecaster. So on the appointed day I turned up at London Weather House with a spare bow-tie in my pocket and joined the other hopefuls.

The first test was one that we could all do together. The examiner sat us all at different desks and gave us the bare bones of a weather situation.

‘Right, listen carefully to this resume,’ he said. ‘It's mild now, but it's going to be colder tomorrow. Today's rain may clear away by tomorrow, but not necessarily. All right, turn that into a weather bulletin. You've got one minute.’

When a minute had passed, he went round the room, listening to our bulletins.

‘Temperatures are going to start dipping sharply in the next twenty-four hours...’ started one girl.

‘Next!’ he said.

‘We're in for a cold spell starting tomorrow...’ said the next man.

‘Next!’ he said.

It was my turn now.

‘Well, if you should happen to be going on holiday tomorrow or just away for the weekend, I'd advise you to take some rain clothes and some warmer wear, because it's going to be extremely changeable and unsettled...’ I said.

‘Excellent!’ he said, and everyone else looked daggers at me. When they had all had a go, he came back to me.

‘This man's got the right idea,’ he said, ‘because he started off in a chatty way and then hedged his bets. The rest of you sounded way too definite, as if you knew what was going to happen. As if you were some sort of expert. Changeable ... unsettled ... scattered showers... these are the words we want to hear! The golden rule of weather forecasting is to cover any eventuality...’

‘But you told us what was going to happen, sir,’ said a girl, defiantly. ‘Why shouldn't we sound definite?’

‘Tell them,’ said the examiner to me.

‘Because you've got to guard in advance against the forecast getting it all wrong,’ I said. ‘Because weather often changes its mind after the forecast has gone out. Because if you forecast rain, and it doesn't rain, people don't mind, but if you say it's not going to rain and it does, people are furious.’

‘That's right! So the golden rule of forecasting is...?’

He pointed at a young man with a small moustache.

‘Er ... Lincolnshire is the only county that gets mentioned separately?’

‘No. You?’ he said to me.

‘The golden rule is always to make the forecast worse than the weather's really going to be.’

‘Good! We know that the forecast is always going to be wrong, so we might as well take advantage of that and make it worse than necessary. Right - now let's see how good you are at remembering symbols on a map behind you which you're not allowed to turn and look at ...’

The upshot was that I passed with flying colours and was accepted for an eight-week training course. I learnt how to say, ‘If we just look at the latest satellite pictures,’ knowing that the audience couldn't tell the difference between the latest satellite pictures and a Jackson Pollock. I learnt how to say, ‘Interestingly enough, they've had some very bad storms in the Middle East today,’ knowing that nobody found it remotely interesting. I learnt how to say, ‘You won't be surprised to learn that this month was the wettest September on record...’ knowing that nobody would dream of disputing this highly dubious statement.

I soon felt confident enough to go to the head man and suggest an innovation in weather forecasts.

‘Sir, it strikes me that you could introduce a new feature into the weather forecast where you looked back to yesterday's forecast and see where it went wrong, and tell people why...’

Five minutes later I was out on my ear. And that is how I learnt the real golden rule of weather forecasting, which is that you must never never NEVER compare what happened yesterday to what the weathermen said was going to happen.

The Independent Monday Feb 12 01