QUESTION: I have been going out with my boyfriend for five months and we have a really good time together, both in and out of the bedroom, except for one thing - he keeps asking if he can spank me. I find the whole idea a bit ridiculous and a turn-off. What should I do?

ROWAN SAYS: There's a good reason why the French dubbed chastisement le vice anglais; quite a few Brits do seem to harbour an erotic attachment to the notion of corporal punishment.

When the psychotherapist Brett Kahr published the results of his British Sexual Fantasy Research Project in 2007, he found that around 18per cent of British men and 7per cent of British women fantasise about spanking someone, while 11 per cent of men and 13 per cent of women fantasise about being spanked (in some cases, clearly, spankers and spankees will overlap).

Kahr wrote that if these statistics were applied to the whole population, you could estimate that between five million and 11 million British adults are keen on spanking in the boudoir. When I edited The Erotic Review magazine, I was amazed at the prevalence of chastisement fantasies - particularly among older male readers.

I remember one septuagenarian writing in and asking 'to see more pictures of lovely, red rumps being spanked by a paddle in your august publication'. But the fantasy was by no means confined to the oldies: a twentysomething convent-educated Erotic Review writer used to pop out in her lunch hour dressed as a schoolgirl for one of her boyfriends, who liked to bend her over his knee.

And a number of the magazine's small ads offered, for example: 'Correction from stern governess who likes to issue lines.' Many prominent figures in British life have been outed as CP (corporal punishment) fans, such as Kenneth Tynan, John Mortimer and Frank Bough.

One of Mortimer's former lovers, Molly Parkin, told the barrister's biographer, Graham Lord: 'When it came to love-making, what he most liked me to do was to smack him on the botty.'

Considering the relative normality of the fantasy, and the fact a number of women share it, I think it would be harsh if you branded your boyfriend some kind of S&M freak for even suggesting the notion. In my experience, it's a harmless impulse and few spankers progress to whips and dungeons.

There are sound physiological reasons why spanking enthusiasts find the practice arousing. Devotees will tell you that spanking helps bring better blood circulation to the rump and thus stimulates sensitive areas. A proficient spanker will vary pace and pressure to ascertain what their lover finds most erotic.

The problem, it seems to me, is that spanking is one of those practices that should appeal to the psyche as much as the body. And if you don't naturally entertain submissive fantasies the scenario can swiftly become as ridiculous as a Benny Hill sketch.

If spanking is not your own pet fantasy, it's hard to fake the kind of faux-naive persona that willingly bends over a knee to be told: 'You've been a bad, bad girl!' I once had a boyfriend (yes, former public school) who wanted to smack me with a hairbrush and I am afraid I laughed so much that he had to abandon the attempt. I didn't want to pretend to be 13 when I was actually 23. Fortunately, sophisticated erotic boutiques, such as Coco de Mer and Agent Provocateur (both of which have excellent websites), have proved brilliantly adept at marketing feminine spanking accoutrements.

There's not a whiff of Carry On film about Agent Provocateur's silk blindfolds, nor Coco de Mer's beautifully decorated spanking paddles - the latter come with helpful 'serving suggestions', telling the wielder to make sure they avoid the area near the kidneys and to apply them 'to the lower, fleshy part of the bottom to excite the erogenous zones'.

I think many women would prefer to imagine themselves in a luxurious courtesan-style scenario than play-acting the 'schoolgirl and stern headmaster' drama so beloved of male fantasy.

Having said all the above, you certainly have every right to tell your boyfriend that spanking simply doesn't push your buttons and you don't wish to experiment. If your sex life is satisfactory without spanking, there seems no good reason why it should not continue to be so.

Nobody should have to do anything in bed that makes them feel uncomfortable. Perhaps you could explore other role-playing fantasies and find one better suited to your mutual erotic satisfaction.

If your reluctance proves to be a relationship deal-breaker, it seems likely your boyfriend harbours much deeper-rooted sadomasochistic fantasies than he dares admit to. Far better you discover this now than later.