Time will tell whether the announcement this week of a new Garda investigation into the sex industry proves to be anything other than a public relations exercise.

Many observers regard the move as shorthand for an inquiry into In Dublin and other publications which profit from so-called health studio advertising. However, gardai insist it will be broader in scope, taking in all those who operate and profit from prostitution, including pimps and brothel-keepers.

Either way, there are questions to be asked about whether policing in the State should be swayed by often fickle public opinion, and whether the best interests of vulnerable women in prostitution is best served by further criminalising the industry.

Although loath to admit it, the Garda Siochana has come to accept as inevitable a certain amount of prostitution in cities such as Cork and Dublin, and that health studios and saunas/massage parlours are far preferable to street prostitution, where working conditions are more dangerous.

That is not to say brothels have been given free rein. But many district detective units have put their priorities elsewhere due to difficulties in securing prosecutions, such as getting witnesses to testify, and also because of relatively lenient sentencing.

Take the case of Brian O'Byrne, for example. The 36-year-old from Templeview Row off Malahide Road pleaded guilty last October to operating two brothels in Dublin, from which he admitted making about £19,000 over a four-month period.

His punishment: £5,000 and 240 hours' community service.

In reality it is the prostitutes, not those who control them, who have felt the greatest impact of enforcement measures to date.

In the first two years after the Criminal Law (Sexual Offences) Act, 1993, prosecutions of women outnumbered those of men by 10 to one.

More recently gardai have tried "to be more gender neutral", says Frances Robinson, project leader of the Ruhama Women's Project. "But inevitably they find it more difficult to prosecute men. It's much easier to identify a woman working the street than someone in a car driving around."

While Ruhama does not agree with decriminalising prostitution, it argues that making women pay fines for soliciting under the 1993 Act only exacerbates the problem.

"If a woman needs to pay £200 to the court, who puts up the money? We're finding clients are being asked to pay the fine, leaving the woman to have to repay the client. It becomes almost like slavery. I know of one woman in that situation who has three kids."

The mixed results from such policing measures have caused law-enforcement agencies in other countries to look at alternatives, including decriminalising prostitution.

Germany and the Netherlands are among the European states which have turned their attention to more pernicious forms of the trade, such as child-trafficking.

Earlier this year the Dutch parliament, swayed by arguments that proper regulation of the sex industry would help reduce the exploitation of women and minors, as well as drugs crime, voted to establish a register of brothels, to put them on the same footing as other businesses.

Under the present law prostitution is legal but brothels are not, although they are tolerated in many cities.

About 2,000 brothels will be registered when the reform becomes law next January, enabling the authorities to keep a rigorous check on the identity of prostitutes and brothel-keepers, and the nature of their work. Penalties for illegal prostitution and child pornography rackets will be toughened.

But not only traditionally liberal European states are turning to regulation. In Britain, a number of city councils are considering introducing licensing systems for massage parlours, ensuring, among other things, regular medical checks for prostitutes.

The initiative was backed in Sheffield last month by a local police commander. He said turning a blind eye to what was going on left those who worked in such parlours unprotected and a target for drug-dealers. Cracking down on brothels, said Supt John Hudson, of Attercliffe, simply resulted in more prostitutes on the streets.

Edinburgh has already broken ranks by granting massage parlours and saunas entertainment licences, a step short of full legalisation. Changing police priorities and a tacit acceptance among the city's decision-makers that brothels provided a safer home base for prostitutes than the streets made the move virtually inevitable.

Glasgow is now considering similar reforms to combat a tenfold increase in street prostitution over the past decade. The debate has been given impetus by the murder of seven street workers in the past six years.

Even the Church of Scotland has backed reform, stopping short of supporting decriminalisation but calling for more practical help for prostitutes and an end to "sexist" laws.

Ambiguity is reflected in policing practices, with one Glasgow police unit devoted to working with prostitutes and offering as much protection to them as possible, and another seeking to prosecute the same people.

Support groups such as Base 37, echoing the view of Ruhama, believe this approach exacerbates the problem. "Making women pay fines only makes them work more," says the group's director, Andrea Denovan. Decriminalisation would help, she says, but because prostitution in Glasgow was driven primarily by drugs, it would be ineffective without a significant investment in treatment facilities.

"People compare Edinburgh and Glasgow and say legalising brothels will solve the problem. But you have to appreciate the vast majority of women working the streets here are drug-users, and while there is a methadone programme in Glasgow it can be very difficult to access," she says.

A similar situation of high drug use among prostitutes prevails here, as a recent Eastern Health Board survey showed. Some 83 per cent of respondents, drawn from Dublin's estimated 200-strong prostitute population, had injected drugs in the month leading up to the study.

While such women, and particularly those who are mothers, are given priority on drug treatment waiting lists, only a small minority can be facilitated. Effectively, they are competing against other women, who account for almost a quarter of the 500 people on the EHB's methadone waiting list.

Increasing access to drug treatment would help to combat street prostitution in particular, says Ms Robinson. As for women working in "health studios", she admits some might do it for financial reasons but often only because they are in debt, or have a family, or feel like they don't have the skills to do anything else.

While she welcomed the Garda investigation announced this week, she says a broader examination of prostitution and greater investment in support mechanisms are needed if the women suffering from the trade are to benefit.

"There is no one solution," she says. "You have to look at each individual's life and ask why any particular woman would seek to sell her body."