THE woman, a thin, rangy brunette, sways slightly back and forth in the doorway. Her long hair is pulled back, emphasising hollow cheekbones and sunken, empty eyes. She seems oblivious to the bitter cold wind as she snaps repeatedly at a cheap lighter, trying to get her cigarette to catch. Before long, she abandons the attempt for a nicotine fix and lurches towards a passer-by. After the briefest of conversations, she links her bony arm through his and leads him into the night.

In a parallel universe, she might have been a model. But in this one, society has deemed her existence worthless.

The office blocks of Glasgow's business district have barely emptied before the streets start filling up again. This time, the service for sale is sex, and the market is burgeoning.

The women - some dressed in the stereotypical low top, short skirt, and high-heeled boots, others clad more casually in jeans and trainers - stand alone or in twos on the street corners, chatting on mobile phones, arranging where and when to meet their regular clients.

This is a nether world, where drugs and bodies are cheap, and where the only people not out of their minds on heroin are the men cruising the area in their big fancy cars - and the police patrolling the streets.

Watching the action with anxiety but a heavy sense of fatalism is Detective Chief Inspector Nanette Pollock, one of Scotland's highest ranking female police officers, who established Glasgow's street liaison team for prostitutes in 1998.

The detective, who retires next month after 30 years' service with Scotland's biggest police force,

doesn't buy the myth that women choose prostitution.

''Imagine having to go down there,'' she says with a sigh, nodding towards the couple as they disappear down a narrow, pitch-black alleyway, ''and have to get down on your knees, among the empty cans in the gutter and the stinking bags of rubbish, to give some guy you've just met a blow job.''

In her view, the word ''choice'' is not appropriate when the options are between stealing from shops, stealing from your family, or selling your body to feed a chronic drug habit and, more often than not, a partner's chronic habit as well, or to get money to buy food and clothes for your children.

''We're not talking about women who could have opted for a career in medicine, law, teaching, or nursing, but instead choose prostitution. We're talking about women who have drifted into prostitution as a means of survival.''

Pollock, who is Strathclyde Police's representative on the Routes Out of Prostitution Social Inclusion Partnership, knows most of the women down the drag by name, and all of them by sight.

During her time with the force, spent almost entirely with the drugs squad, the former hairdresser has witnessed the deaths of seven young women working as prostitutes and the destruction of countless more lives and families.

As cheap heroin flooded Glasgow's streets in the 1980s, it led to a huge rise in the number of women turning to prostitution. There are now estimated to be around 1400 working on the streets, at least 95% of them injecting drug users, as well as 200 to 300 more working in flats and saunas.

''That girl there has serious mental health problems,'' Pollock says, referring to a pretty young slip of a thing, again with a rheumy, faraway look in her eyes. ''In fact, most of the girls have profoundly sad backgrounds. There's an extremely high incidence of child sexual abuse, high levels of physical and emotional abuse, placements in care and homelessness. And in Glasgow the problem is exacerbated by extreme poverty and a chronic drug problem.''

If the women have chosen this as work, it is impossible to find a single one of them who looks happy doing it.

Pollock, a tough, but warm, funny, and compassionate detective, is retiring at a time when there is a growing sense of urgency about how best to ''control'' the problem.

In Aberdeen there have been calls for legalised brothels and the decriminalisation of prostitution. At the same time, Margo Macdonald, the SNP MSP, has proposed a bill that, while not exactly legalising prostitution, gives the go-ahead for what would effectively be local authority-controlled toleration zones.

Pollock views the prospect of the former with horror and dismisses Macdonald's proposals as completely unworkable. On a practical level, councils would be responsible for running an area for prostitutes to work, where the law is not enforced. Pollock says a true toleration zone means no policing, which would make it even more dangerous for women.

Instead, she remains absolutely convinced that Glasgow's robust multi-agency approach is the best way forward. The city has taken flak for its stance, with critics saying it should be following in Edinburgh's more enlightened footsteps.

In fact, there are more similarities between the two cities than differences. Edinburgh wants to be able to re-establish a toleration zone. Glasgow has an unofficial one, where women are not arrested for soliciting and which is patrolled by plain-clothes officers and monitored by CCTV cameras.

The capital has Scot-Pep, a scheme aimed at promoting safe working practices for prostitutes, and it boasts of having no new cases of HIV. Glasgow has Base 75, a joint social work and health service project, providing medical care, emergency access to accommodation, and free needles and condoms. And, like Edinburgh, there has been a significant reduction in known HIV infection in the past 10 years, from 38% of women in 1989, to no women testing positive in 1999.

The two crucial differences between the two cities is that most of Glasgow's prostitutes work on the street, while the majority of Edinburgh's 800 prostitutes work in saunas and massage parlours.

The second is that the focus in Glasgow is on getting women out of prostitution and trying to prevent vulnerable youngsters entering it, rather than just accepting that it's inevitable - an argument which, Pollock insists, is a self-serving one put forward by men. She is vehemently opposed to any moves to regulate, and hence normalise, prostitution.

''I know Glasgow has a different stance from Edinburgh and Aberdeen, and I am so glad,'' Pollock says. ''At long last we have got what's been needed for so long - a policy that recognises that prostitution, whether it takes place in saunas or on the street, in a lane in a toleration zone or a room in a five-star hotel, is an act of violence against women per se.

''In actual fact, you tend to find that in saunas women have even less control over what services they will perform. On the street, very few women will do anal and few do sex without a condom. But in the saunas, the owners, who obviously don't want their punters going away disappointed, decide what the women will do, and very often that is anal sex and sex - oral and vaginal - without a condom.''

She accepts that there will always be a small number of ''professional prostitutes'' who live in lovely apartments in nice areas and have their own regular clientele, who, for whatever reasons, decide to make their living by selling their bodies. She doesn't have a problem with this because in her opinion these women genuinely do have a choice.

But she insists that most women in prostitution, whether they are working from a sauna or on the street, are doing so because of a lack of choice.

It was Napoleon who claimed, in 1827, that prostitutes were a necessity because ''without them, men would attack respectable women in the streets''. His words summed up beliefs still held in some quarters today - that men are innocent victims of sexual desires and women exist to service them.

The very philosophy behind the legal regulation of prostitution, which dates back many centuries, was to control women ''as purveyors of the diseases of syphilis and gonorrhoea'' and to protect the ''morally blameless'' men who fell victim to them. Such attitudes hold no truck with Pollock. She is not a man-hating, sex-fearing, narrow-minded prude. She simply believes in equality for women and laments the fact that as the debate rages on, the focus is still fixed entirely on the women selling sex rather than the men who pay for it.

''This is something we have failed to address time and time again,'' she says. ''We are always talking about the women, about how vulnerable they are, and about the murders and the violence, and why they do it and all the rest of it, but we fail to talk about the demand for it.

''I think we are going to have to address the men's behaviour. There are an awful lot of married men who, for whatever reason, come in and seek the services of a prostitute.

''They have remained invisible in this whole debate for too long.''

A comprehensive study of private attitudes published in the Observer last year revealed that 10% of men had paid a prostitute for sex. Another study, carried out in Australia, found that around 80% of brothel customers were married men.

But, says Pollock, you could ask 100 men in your office or among family and friends, and the chances are none of them would put his hands up and say ''Yes, that's me.''

''The reason for that is because it is basically very difficult for them to justify their behaviour,'' she says.

In describing the appeal of sex with a prostitute, researchers from Glasgow University identified five aspects: the capacity to specify particular sex acts they wished to perform or have performed on them; the capacity to have sex with different women; the ability to seek out women with specific physical attributes; the thrill of doing something that is socially frowned upon; and the limited and unemotional nature of the contact with a prostitute.

Pollock, who is married, has her own ideas about why men buy sexual services. ''An awful lot of it is about power and control. The fact that a man can come in and buy sex, some of them think they have actually bought this woman and can do whatever they like with her. Basically, the woman is just another commodity.''

Pollock believes that the Routes Out SIP, which was established after the murder of Margo Lafferty in 1998, is proving successful. She stresses that it can take between three to five years to get people out of prostitution and says the 100 women already referred to the scheme provide evidence that women want to have other choices and opportunities.

The scheme has also been given the seal of approval by local authorities and police forces in England. Two weeks after she retires, Pollock has been invited to deliver a series of lectures about the way Glasgow is dealing with the problem.

Back out on the cold, dark streets in the city's red-light district, Pollock admits that the eradication of prostitution is pie in the sky. ''Of course we will never eradicate prostitution, in the same way that we won't eradicate poverty or homelessness. But it

doesn't mean we shouldn't try. To do that is simply to abandon women to what has to be the most demeaning job in the world.''