ONE irrefutable fact emerges from The Herald investigation into prostitution: the complexity of the problem, even in a country as small as our own. We deceive ourselves if we pretend to believe in a monolithic prostitution that needs only one solution to smash it. Leaving aside the blatant slavery of Third World prostitution, it is glaringly obvious that, even within our restricted borders, there are variations enough to preclude the possibility of one overarching remedy designed to put all to rights.

Prostitute is a portmanteau term. What, after all, does a call-girl of the Christine Keeler variety, cavorting with Cabinet Ministers and celebrities serenely immune from police prosecution, have in common with an Anderston junkie, squalidly dicing with her life, cowering in doorways at the first glimpse of a blue uniform? We call them both prostitutes. We might just as well call Allesandro del Piero and a Saturday youngster, footballers, because they each kick a ball.

The mind lazily embraces the imprecise word because it saves us from having to think. For if there are different kinds of prostitute and prostitution, then it follows that there must be appropriately different approaches, and it is entirely conceivable that what might be helpful in one instance might be mistaken, even dangerous, in another. A doctor who advised every patient, willy-nilly, to eat less and exercise more, might end up doing more harm than good. Empty your streets and open your saunas. Good advice for Edinburgh but, perhaps, in the very different circumstances of Glasgow, utter disaster.

If nothing else, The Herald investigation showed us that there is a Glasgow, an Aberdeen, an Edinburgh, a Dundee, prostitution, no two alike, each calling for its own particular medication. Under the deceptively unifying word are the radically different interpretations.

The same heterogeneity can be seen in the comments of the women themselves - were they really talking about the same job? A 24-year-old junkie from Anderston told us that she ''would not wish this on my worst enemy'', but for her drugs problem, she would be somewhere, anywhere, else. By contrast, a

45-year-old ''masseuse'', living near Bristol, commuting by plane weekly to Aberdeen, remarked that she enjoyed her work and meant to go on as a one-woman business, with no intention of giving part of her profits to a sauna. Hers is clearly a deliberate, rational career choice, based on purely economic grounds; she has tried being a barmaid, cashier, etc, but the pay isn't as

good. Are these two women in the same profession?

It might be helpful to distinguish the various ways in which the path to prostitution is taken. In an ideal world there would be only upright men and virtuous women, strong families and cherished children. But this ideal is impossible and this world does not exist. No mother wants her son to grow up to be a ''punter'', no father wants his daughter to end up on the streets or in a sauna. But some do.

The next best situation (and this is attainable) is a world in which the only prostitutes are those who have deliberately, calculatingly, chosen to be so, and who can, accordingly, decide at any moment to change their minds and profession. This is as good as the world gets.

The worst, the intolerable and unacceptable, situation is when women are coerced, no matter how, to become prostitutes against their will. This is an abomination and this is the world we live in. I am referring not to the countries of the Third World, but what is happening nightly on our city streets.

There are different modes of slavery (economic,

drug-induced, etc), but there is one common element - these

women are prostitutes by compulsion, not by choice. Our attitudes towards these and the clear-eyed, rational choosers must be very different. The willing prostitutes must be left to themselves - what else is there to do? The unwilling prostitutes, victims twice over, trapped in their Dantean circles of destitution and addiction, deserve every help to escape this doom.

It is prostitution as enslavement (socio-economic or drug-induced) that must be fought against tooth and nail. The other kind we must learn to thole, but slavery is a curse not to be endured. Cardinal Winning recently outraged some people by saying that a starving man has a right to steal a loaf - why should not the same allowance be made to a starving woman who sells her body? If we don't want men to steal and women to prostitute themselves, remove the necessity - until then, any condemnation is a boomerang. If an unjust society produces thieves and prostitutes, build a just society. Free the slaves, or, at the very least, stop blaming them for their slavery. And if this is true of those who are the slaves of poverty, how much more so is it of those who are the slaves of drugs?

How, then, do we effect such a liberation? It has been frequently pointed out, that, were we really determined to attack prostitution, we would target the male customer rather than the female supplier. It seems logical. It is not the supply that creates the demand, but the demand that creates the supply. Businesses fail because the goods and services they provide are unwanted. If there are no buyers, there can be no sellers. Yet, with prostitution alone, the opposite has been assumed: in what other

trade is it a crime to sell, but not to buy? No customers, no prostitutes. It is what the logicians call a

contrary-to-fact conditional. Prostitution is not going to go away, so how best can we restrict it to the lowest possible minimum?

First, by ensuring that there is not a single woman in prostitution simply because she has nowhere else to go. An escape route must be provided for every woman who wants out, and this means attending to the socio-economic and drug problems that have taken her there in the first place.

Second, given that prostitution is a literal exploitation of women, how do we set about eradicating it? Not, surely, by legalisation, for what else does that do but make it acceptable? In any case, legalisation of itself will not provide a barrier against HIV or other sexually-transmitted diseases, against violence, drugs, etc. Far

from helping the ever-swelling number of addict prostitutes, legalisation would simply drive them further underground.

The real task is to rescue the victims, not confirm them in their victimage. Just because you become a taxpayer, doesn't, of itself, confer automatic immunity from violence, assault, and rape.

Decriminalisation seems, by far, the preferable option. We should stop victimising the victim, finding her guilty of the offences committed against her. Remove the prostitute's fear of being charged. Fines, far from bringing her back to the paths of righteousness, are surely going to thrust her further down the road to ruin. End the absurd practice of imposing a fine for soliciting, which compels the penniless offender to repeat the offence as her only way of obtaining the money to pay the initial fine - if you really want to get somewhere, the last place to be is stuck in revolving doors.

When, finally, all is said and done, there is one last, undeniable test: set people free to choose - for how else can they be held accountable?