SUPPOSE you are a 60-year-old rich, successful businesswoman. You go out to dinner and a tall, dark, handsome 30-year-old stranger starts chatting you up. He immediately asks you out to lunch, then tries to bounce you into a hotel bedroom upstairs.

Would you not think this behaviour a mite suspicious, that his motives were not of the purest? In the natural order of things young men are attracted to young women, not old women, even with the help of cosmetic surgery and millions in the bank. A sensible person would make their excuses and leave. If I were the woman I hope I would sense trouble before passion rendered me blind.

So when young women appear to be swept off their feet by powerful or wealthy old men, a more complicated deal, as old as time and distressingly untouched by decades of sexual liberation, is being transacted. To spell it out: forces other than mutual passionate attraction are almost certainly in play, even if that is present, too. And those forces intensify with the size of the age gap.

For the woman it is a short cut to a lot of things she may desire - security, attention, money, position - but be unable to achieve by herself, or with a partner of her own age or social background. For the receptive man the experience may be an ego boost, a refreshment to his libido, or an opportunity to bag a trophy wife.

Given that this is one way of the world, is it not amazing that not one but two men with solid achievements and public careers were so silly in reacting to the very obvious encouragement they received from the dodgy Bienvenida Perez-Blanco. With an invented background and so little to lose, was there ever a chance she was going to be a suitable wife or a discreet mistress? Of course not.

Could they not work out for themselves that a 24-carat gold menace, disguised thinly in short-skirted designer outfits, had zoomed into range, and should be avoided by the prudent at all costs? Sir Antony Buck had a long career behind him as an MP. Sir Peter Harding was apparently wise enough to rise to the head of our armed forces.

Moreover, as a career soldier advising the Government on all matters military Sir Peter had given himself over to a disciplined way of life which stresses the value of dispassionate decision-making and clean living. Looking at the lady on the one hand, and her suitors on the other, I am left asking the question: why are some men so daft?

I detect here an interesting division between the sexes. A number of men seem to be relatively understanding of the behaviour of Sir Antony (who, after all, married the woman and financed her high living for several years before collapsing into the exclusive embrace of the Sun) and Sir Peter, whose career is finished because of her.

'Beautiful women are very hard to resist' is one explanation. 'It would be exhilarating,' said a middle-aged man when asked what he would do if a much younger woman chatted him up. Successful men say, with scant sign of displeasure, how they are frequently targeted by predatory, inevitably younger women. It is all part of the glorious business of reaching the top, confirmation that you possess the aphrodisiac of power.

But what surprises me is that men, men of the world, react so helplessly to unsubtle sexy cues of the sort thrown out by Miss Perez-Blanco. It is as if they still have a strangely hopeless, old-fashioned, two-dimensional view of femininity which makes them unable to deal with calculating women in the round. Neither Sir Antony nor Sir Peter, for all their worldly wisdom, were a match for a glamour puss on the make, prepared to take the money and talk. I feel quite sorry for them.

I'm not arguing that elderly men should be deprived of extra-marital sex with younger women if that is what both sides crave. Or that true love cannot leap age barriers. But a lot of well-known middle-aged and elderly men seem strangely child-like in their reactions to the siren calls of sex. In an unequal relationship, just be prepared for tears.