John is not typical of the homeless. Well educated and articulate, he has slept rough for five years, ever since his wife died. Since his loss, John has sought refuge in the bottle; he has lost his job as a teacher and his home. He looks 70, with what can only be described as weathered features - but he is in fact 51. He clings to dignity by describing himself as a "park-bench poet" - with some justification: he hassles public librarians to get copies of Heinrich Heine in the original German (apparently the translations don't convey the angst of the original). He gives a share of the money he gets from begging to some pensioners he knows. They need it more than him, he says, because he has no bills to pay.
In reality, John is actually typical in his atypicality. Homeless people are almost as diverse a group as the population at large. There is only one thing that almost all of them have in common, apart from the lack of a home: they are male.
As any walk through any city centre at night will show you, homelessness is almost exclusively a male problem. According to the Homeless Network, an umbrella organisation for homeless charities, around 89 per cent of those sleeping rough are men.
Ask any housing expert to explain the discrepancy and, surprisingly, they will tell you that no research has been done on the subject. The housing charity Crisis has recently started addressing the gender aspect of homelessness; it's just commissioned a report into "Homelessness and Women".
One clear reason is that the street is a more dangerous place for women than men. All those sleeping rough are liable to be beaten up by drunk people leaving pubs, but women are especially vulnerable and tend to make more use of emergency accommodation. But even in these "direct-access shelters", men still outnumber women four to one.
Four to one. Compare that to eight to one on the street. Like public toilets, direct-shelter beds are almost all allocated by gender - there are roughly twice as many emergency beds available for women sleeping rough as there are for men. The end result is inevitable: while there are often vacancies for women's accommodation, for men the shelters are usually full.
"There are nights when there are no male spaces available, so the men go rough, while there are still spaces available for women," says Kate Tomlinson, manager of policy at Crisis. Put another way, it's common for homeless men to turn up at emergency accommodation and be told, in effect, "If you were a woman, we'd have a bed for you."
Women - particularly young ones - are also less likely to be officially homeless because they are liable to be drawn into prostitution or abusive relationships that have the one saving grace of taking them off the street.
The main economic cause of homelessness is unemployment. The destruction of male-dominated unskilled manual jobs and the creation of female-dominated service jobs has left many men at a disadvantage in the labour market. Government figures show that men are twice as likely to be unemployed as women, and three times as likely to be long-term unemployed. Homelessness is often only a step away.
"The routes into homelessness are dominated by men," says Tomlinson. "Whether it's prisoners being released to the outside world, soldiers leaving the armed forces, young people leaving care, dependency on alcohol or drugs, or losing accommodation after the breakdown of a relationship, men outnumber women."
There are 20 times as many male prisoners as female ones; and according to the National Association for the Care and Resettlement of Offenders, half of them have no home to go to after release. The probation service does its best to arrange accommodation, but admits it often just can't cope.
"The probation service is not an accommodation agency, and we can't guarantee that people find a place to stay. We'll try, but there are times you can't even get emergency accommodation," said a spokesman for the Inner London Probation Service, the largest in the country. He added: "It can happen that people spend their last night of their sentence in prison, and then spend the next night on the street." This is not nice for the former prisoner - and especially not nice for society: it is difficult to think of any way more likely to make a former prisoner re-offend than chucking them out on the street.
The prison story is repeated with another great institution of the state: the army. Roughly one in five of those sleeping rough ended up on the streets after leaving the armed forces with nowhere to stay. Again, it's almost all men. "You just don't find homeless women soldiers," says Tomlinson.
Soldiers need far more help than is usually realised, according to David Warner, director of the Homeless Network. "If you've been a squaddie for ten years and everything has been done for you and your life has been organised for you, then what you need is rehabilitation." The army isn't totally oblivious, according to Tomlinson: "It gives them a book," she says ironically.
The picture is similar, if less extreme, in care: young men in foster homes or institutions outnumber young women by roughly three to two; of those who leave care and end up on the streets, boys outnumber girls by about four to one. Peter Hardman, the director of First Key, sees many reasons for this. Boys, for one, are more likely to fight and then fall out with their foster families than girls. "Young women leaving care are more readily accepted back into the immediate or extended foster family," says Hardman. "There are more young women who have converted the foster placement into lodging."
Pregnancy, too, plays its part. Various studies show that between one-seventh and one-quarter of young women who leave care are already mothers, and local authorities are legally required to give them accommodation. Hardman says: "All sorts of child- protection issues come to the fore - they're in the safety net. Many local authorities have mother and baby units. Young men who are fathers don't tend to stay with the children and don't get accommodation."
Many of those involved with the homeless mention this legal assistance in explaining the difference in homelessness rates between men and women. Nicholas Pleace of the Centre for Housing Policy at the University of York says: "Homeless women are far more likely to be with children, and thus tend to get assisted under legislation. The only other way of getting statutory assistance is by being classified as 'vulnerable', such as having mental health problems - but that's so much more difficult to identify."
Yet institutional and legal issues alone don't explain the extreme disparity between the number of homeless men and women; what does emerge from this grim picture of gender inequality is men's inability to help themselves in times of crisis.
Megan Ravenhill, a researcher at the Centre for the Study of Social Exclusion at the London School of Economics, has recently been interviewing homeless people about their lives, and says a clear pattern is emerging: women have better, stronger social support networks. "Women tend to spend longer sleeping on friends' floors because they're less likely to fall out with their friends. They're more likely to have a network of friends from antenatal classes, the nursery or the school gate. For men, friendships tend to be based around work, so that once they've lost their job, they lose their social network."
Men's friendships tend to be less intimate and thus less supportive in times of crisis, says Ravenhill, whereas women are more likely to be able to help each other in practical ways because they know friends who have been through it all before and learnt the lessons. "Lots of the men just don't know what to do, how to find hostels or help. They feel totally alone," she says.
Instead of relying on friends, men have other - far more destructive - ways of coping. If marriages fail or they lose their jobs, pride often stops them asking for help, and they are far more likely to turn to drink or drugs. Homelessness beckons; the risk of suicide rises.
Children can also be a stabilising factor in women's lives. Many people become homeless after their marriage or relationship breaks down; when children are involved, it is far more likely that it is the man who leaves and has to find somewhere else.
But social attitudes take little of this into account. Men are meant to be strong and should be able to look after themselves - otherwise it's all their fault. "There's a lot of stereotyping that goes on - it's almost the Victorian idea of the undeserving poor, particularly with male rough sleepers," says Pleace, "and because of the way we think about homelessness, they're seen as an undeserving group."
Understanding why women generally manage to avoid homelessness and men don't suggests many simple steps to alleviate the problem. Ravenhill suggests an education campaign aimed at vulnerable men, giving them practical advice on how to avoid homelessness in the first place. Male pride could be overcome, she suggests, by challenging the images and the stereotypes. The simple measure of renaming "homeless hostels" as "working men's hostels" to help those still employed but out of home could make a real difference, she says.
The government, too, could take many simple measures to ensure that men aren't pushed straight out of institutions on to the street. The army could provide more care for its servicemen, the probation service could be legally obliged to ensure that no prisoner spends his first night of freedom sleeping rough and, as the government's own Social Exclusion Unit has suggested, local authorities could be required to provide housing for all youngsters leaving care, not just mothers.
There are signs that the new government is taking the causes of homelessness more seriously. The Social Exclusion Unit has taken a cross-departmental approach, which has been warmly welcomed by homeless groups, and made many sensible proposals. But like many of those above, they are likely to cost a little bit of money: money for a group which is not usually deemed to deserve it.
Anthony Browne is the economics correspondent for the "Observer". He is writing a report for the think-tank Demos on why men are failing