The most powerful headline I ever read and acted upon was a negative headline. It changed my life.

Yet most books on direct mail copywriting will tell you to cast your headlines, overlines and Johnson Boxes always in the positive. But sometimes being negative is positively good for business. Or, to say it another way, negative headlines in your direct mail advertising are not always bad.

The headline that changed my life appeared in a small display ad in the Daily Mirror, a British daily newspaper. Here’s what it said:

“No Pleasure Cruises in the Royal Marines.”

That’s a negative headline, no question. The copywriter wasted no time turning a negative into a positive. In fact, he turned a positive into a negative.

Beneath the headline was a photo of several heavily armed Royal Marines crouching in a rigid raider assault boat, manfully pounding over the waves towards an assuredly nasty landing on some distant enemy beach.

Beneath the photo was this simple body copy:

“Some of the toughest training in the world. That’s what makes Royal Marines Commandos ready for anything. If you think you’ve got the determination and you’re over 16, here’s your chance. Find out more by sending off the coupon.”

“No Pleasure Cruises in the Royal Marines.” When I read that negative headline for the first time, I was slouching at the back of mathematics class, catching up on the comic-strip misadventures of Andy Cap and Hagar the Horrible. The year was 1976. I had just turned 16. My Oxford and Cambridge ‘O’ Level exams — and certain defeat — waited less than a week away. I read the advertisement again. I studied the photograph. I mailed off the coupon that night.

The information package arrived within the week. Nine months later I was PO35440S Junior Marine Sharpe, bayonetting dummies with gusto and throwing up my lunch during nine-mile speed marches. Eighteen months later I was dodging bullets and bombs in Northern Ireland. Five years later I was photographing penguins in Antarctica. Ten years later — and thirteen countries, four promotions, numerous fights and a Falklands War later — I was a civilian again.

That headline would not have worked for me if the copywriter had cast it in a positive way. By promising what I would not get, and by telling me what I should not look forward to, he won me over.

So here’s my advice. Don’t turn all your negatives into positives. Instead, turn your positives into negatives for a change. Don’t be timid.