I have only ever given my children one piece of advice. Other parents I know talk solemnly about drugs, sex, pregnancy, work, manners and the importance of good A-level grades. But all I’ve ever told my kids is this: “No matter what, never salute a magpie.”

I don’t know when I got into the habit. Or even why. Maybe it was peer pressure. Maybe it was boredom. But one day, while driving along, I saw a lone magpie hopping about on the grass verge and I saluted it. And that was that. I was hooked. And now, I know for sure that if I fail to salute even a single one of them I will catch cancer within the hour.

This is a huge problem in Milton Keynes where, for reasons known only to Bill Oddie, there are one trillion magpies, all of which hang around by themselves on the endless sponsored roundabouts.

I’d love to know how many people die on the town’s roads each year because the driver was warding off bad luck. I bet it’s millions.

All superstition is mumbo jumbo. I know that. As a result, I will happily walk under a ladder, and I know that if some bees come to my house it will not burn down. I realise too that a black cat will give me just as much asthma as a brown one and that if my left ear feels warm it’s because it’s a sunny day. And yet I have this magpie thing going on. It makes me very angry as there is no methadone. There is no clinic. There is no cure.

Still, it could be worse. I could believe in the power of ley lines, the magic of dance and that I have the ability, through deep concentration, to become a dog or a cow, so that I may experience life from its point of view. In short, I’m awfully glad I’m not a druid.

Last June they were at Stonehenge again to mark the summer solstice. Apparently, 36,500 poor souls got up in the middle of the night and were dragged by their beliefs and their little Citroëns to a field in Wiltshire where they were forced by custom to mark the disappointingly cloudy dawn by chanting and pretending to be King Arthur.

As a saluter of magpies, I have every sympathy with these people and I wish them well. I like having hippies in the world. They bring a richness and a calm, and while they like to wear hoods, they do not beat up old ladies.

And that brings me on to the point of this morning’s blog entry. What in the name of whatever god you hold dear were the police doing using an unmanned spy drone to fly around, taking pictures of these people as they swayed gently in stillness of morning?

Can you imagine the hullabaloo if Dixon of Dock Green used similar tactics during a Catholic Church service?  If the smells and bells were drowned out by the relentless buzz of a spy plane? And let’s be honest, shall we? On the crime-o-meter, Johnny Pope’s merry little gang of bachelors is far more likely to be involved in serious wrongdoing than some dizzy druid bird with flowers in her hair.

I can see why the army might need a spy drone in Afghanistan. But how on earth could the Wiltshire constabulary justify the purchase of such a thing? To catch crop circlists? It’s the most absurd thing I’ve ever heard.

And why were revellers limited to taking just four cans of beer each onto the site? This means there must have been a meeting at which a busybody in a trouser suit will have said “two” and then a fat man will have said “five”, and much discussion will have taken place, at our expense, before the figure of four was arrived at.

This is even more absurd, come to think of it, than the police spy plane. Certainly I feel sure that early man would not have embarked on the road to civilisation if he had thought that, one day, humankind would arrive at a point where one man has the right to determine how much beer another man may take into a field in the middle of the night.

Then there’s the drugs business. Now, I’m not going to come here and defend the use of narcotics. But we learnt last week that there are now 1m cocaine users in Britain. Statistically then we can be assured that marching powder is being used in the House of Commons, in village halls, in business meetings, at dinner parties and even, perhaps, by pop stars.

So why pick on the druids? Why send sniffer dogs to their annual summer get-together? We know there will have been some dope and we know, because they’d stayed up all night, that some of the Morris men will have got some marching powder up their schnozzers. But if it’s busts they’re after, Plod would probably have had a higher success rate if they’d had a snout about in their own locker rooms.

The fact is that despite the massive, and extremely costly, operation the police made only 37 arrests, mostly for minor public order offences. That’s 37 from a crowd of 36,500. One in a thousand, or thereabouts.

I’m not suggesting that the police ignore large gatherings of people.

Whether it’s a football match or a bunch of Tamils in Parliament Square, the forces of law and order need to be on hand to give people directions to the nearest bus stop and break up whatever fights may occur.

But I simply cannot understand why such large numbers were used to monitor a group of people who, by their very nature, pose about as much threat to the world as a flock of budgerigars. They hum. They make love to one another. They speak in Welsh. And they go home.

Certainly I can assure you that driving along while under the influence of a silly scare story about magpies is much more of a threat to the nation’s peace and tranquillity.