There is a beautifully simple logic behind the proposals said to be under consideration by the government to criminalise men who pay for sex – apply the laws of supply and demand. If the demand is wiped out by tough laws, the supply will wither on the vine.

The argument continues that women involved in prostitution are victims of coercion by evil pimps or in the grip of addiction to class A drugs. They know not what they do and are in urgent need of rescue. It is not fair to punish them with Asbos, soliciting convictions and the like, when it is men who are to blame for their miserable predicament.

One problem with this argument is that it oversimplifies a highly complex area in which women have a huge range of different experiences.

Only a small percentage of women involved in prostitution work on the streets. Most of this group have chaotic heroin and crack habits and are working primarily to support them. The majority of sex workers are based off the streets, in flats or saunas or as escorts. Generally they are not addicted to drugs. In some parts of the UK, up to 80% of the women working indoors are from other countries, but only a minority of them are trafficked. According to Lithuanian anti-trafficking police, even trafficked women often know that they are coming to the UK to work in the sex industry. They make the decision to come because they are living in poverty. What they do not know is that once they arrive they will be subjected to enormous cruelty by their traffickers and deprived of their liberty and earnings.

Ideologically unpalatable though it may be to some, the majority of women involved in prostitution have made a choice to sell sex, because they see no alternative way of earning what can sometimes be substantial sums of money. Undocumented migrants in particular have few options available to earn money. The twilight world of prostitution in a rich western country is one. Their goal is to lift themselves and their families out of poverty, and they see this as one of the few ways they can do it.

A key issue for the government to consider if it does go down the road of criminalising men who pay for sex is that it does not appear to work. Such a law was introduced in Sweden eight years ago, but research has shown that instead of wiping out street prostitution, it has simply become more hidden, placing the women involved in it at greater risk of violence from punters. The most socially marginalised women who work on the streets have suffered most. Meanwhile, sex for sale on the internet has increased.