"We did it too," she wrote. "And some of us still do."
Every so often there's a story about "love finding a way" featuring lovers of at least 70. They may have lost touch during the war and married other partners. When one died, the survivor somehow or other met up again with his or her first love, by this time also alone. Of course, we wish them well and happy. And either give it no further thought or imagine that keeping each other's backs warm and the chaste kiss they share for the cameras is all they're up to.
Or there is a story about a heart attack or a potency pump and the wife, quoted, says what a relief it is, because "that side" of their lives was always so good, how depressed he became when it failed but now everything is all right again. No details, these are nice people.
Of course, if you're rich and famous and ageing, a film star, a luminary of the international media or monetary circuit, then you are either so stylish we don't think about what you do sexually but imagine it's all aesthetically arranged. Which is to say, out of sight. Or else, if you are still putting it about, it's probably with somebody at least 20 years younger.
Or you're Camilla Parker Bowles and Prince Charles - neither young nor oil paintings but clearly having a nice time, thank you.
It's OK to fall in love if you're older - especially if it involves suffering and making do, or doing without. But sex, whether gymnastic or emotional, is reckoned to be the preserve of the young.
To say all the images surrounding us enforce that point will tempt some smart alec to write in and point out that such-and-such company does feature a woman of over 50. But 50 is only the beginning of the age group of which we speak. Fifty - especially a female 50 - has very few photographic images outside the business pages or the political headlines. Helen Mirren may have been voted the sexiest woman on TV in May, but the picture of her naked on the cover of Radio Times hardly revealed her in all her 50- plus glory.
Fifty is OK if it looks like 36 in full camera make-up - step forward, Joan Collins, Goldie Hawn - but even the most imaginative and prestigious photographers find it hard to offer us any variety of women at that age. Following the American model, you spend a great deal of your time, money and energy attempting, Canute-like, to hold back the tide of age. And most men don't fare any better.
And what you look like dictates what you can do, or should be seen to be doing, or might be doing. So sex has become a kind of narcissism in which smooth thighs or midriffs like sixpacks permit the young or relatively young to look for mutual reassurance in the reflections from each other's eyes. Such sex is close to a kind of exam in social acceptability, redolent of that awful phrase "as normal as cleaning your teeth".
Part of the confusion stems from the way the language of sex and love is confused. It's all right to love at any age. Love is decorous and attractive but sex involves a different kind of giving. Sex is sweaty, animal, often deeply unbecoming and better realised by inference than by simulation.
Angela Lambert's latest novel Kiss and Kin features a Romeo and Juliet qualified for their bus passes - and brought her brickbats. ("Wince-making sex scenes" - unnamed reviewer in Ideal Home; "the characters are impossible to sympathise with" Teresa Waugh in The Spectator). Passion could not be for people of that age. Such an idea is irresponsible, untidy and repulsive. Repulsive to whom? Do they not like doing it or do they just not want to have to think about it? Whether you like her book or not, all Lambert did was to give substance to the idea that, however old the body gets, the heart stays young and hopeful. Why is that such a disturbing notion?
There are plenty of men and women who still think that sex is for babies. And plenty more who thank God when the babies are got and they can look for somebody else to give them pleasure. And there are just as many who think - along with their teenagers - that sex is not for anybody over 40 or a parent, which we always used to attribute to the natural prudishness of the young.
For the rest of us sex remains personal, private and infinitely variable. Not an imperative but a cherished option, an accessible non-addictive comforter. And if we are among those unsung many who have made marriages and partnerships last 20, 30 and 40 years - even if we are now told that fewer and fewer people will live that way in the future - why shouldn't we enjoy ourselves in the simplest, cheapest, most life-enhancing way we can?
We don't need to be told how we should look when we make love. We need to be cherished for the bonds we share, for the trouble we have survived. This is the very opposite of Cartland country. In the lives of the sexual silent majority, lines and shadows are smoothed out in the kindly dark and if we bump and pant and groan, shedding tears or giggling, whose business is it but ours?
Perhaps in the matter of sex as in love, the more we know, the less we know - and many of us are too afraid to continue into the unknown. The images of sex get in the way of the personal journey. When you have not had sex for a few weeks, you may feel more vulnerable and naked and less like whoever your pin-ups are, than when you did it every night for the sheer joy of doing it. And all too easily that becomes not sharing sex, not sharing talk, not sharing intimacy - though frequently remaining a good provider or keeping the kitchen floor fit to eat off.
In a world that talks endlessly about everything, there are few generalisations to be made about how partners conduct the intimate side of their lives. What we know is that if routine and ritual shores one couple up, it may break another down. But when Marie Lloyd sang "A little of what you fancy does you good", she was not talking about cake. And if you fancy it, why shouldn't it be on your shared and mutual terms, and devil take the double chin and all those insidious images?
At 60, you don't have to be rogered on the bonnet of a Rover like Billie Whitelaw in the TV series Born to Run to have a sex life that makes you feel all of yourself instead of part of it. The journey through life is long, the scenery various and different people make different journeys and appreciate different scenery.
Tina Turner sings: "What's love got to do with it?" I say: What's age got to do with it?