Most of us tend to associate homelessness with men. But spare a thought this Christmas for the hundreds of female rough sleepers, who make up around one in 10 of the homeless population.

These women have often ended up sleeping rough after running away from a violent spouse or partner. Some resort to drugs and prostitution to help them survive.

Leading homelessness charity St Mungo's runs two women-only hostels in London and another in Bristol. It says that the number of homeless women in London is rising - from 2011-2012 women comprised 9 per cent of the homeless total but this figure had gone up to 11 per cent from 2012-2013.

"The economic situation affects individuals," St Mungo's director of new business Alexia Murphy says.

"People are losing their jobs and becoming homeless. I am particularly worried about female rough sleepers because they are already on the margins of society."

Murphy explains that by the time women seek out St Mungo's services their various problems - such as mental illness, drug dependency and other health issues - are often well and truly entrenched.

With the exception of alcohol use she says that homeless women come to them with a greater number of complex concerns than their male counterparts.

"They are vulnerable to these problems because they have not grown up in an environment that cares and supports them. They didn't get what they needed [when they were young] so they have self-esteem issues and their problems are replicated."

The majority of homeless women have children but they are often taken away from them and placed into care, thus increasing the woman's sense of isolation - and guilt.

Murphy says that whereas men tended to relate what the world did to them when they first approached St Mungo's - "I was given the sack, my wife threw me out" - women were apt to tell you what they did to the world ("I lost my child.")

And despite a steady increase in demand there has been a significant cut in their services specifically targeted at women due to a reduction in funding.

Professor Kate Moss of the University of Wolverhampton has been researching the phenomenon of female rough sleepers since 2009.

She took part in an EU-funded project which investigated the problem in Britain, Sweden, Spain and Hungary.

She was also involved with a campaign organised by St Mungo's last year called Rebuilding Shattered Lives.

Moss says that it was difficult to know the true number of homeless women because they were often hidden. They may sofa-surf or hang out in a bar, snooze on a night bus or even pretend to be a holidaymaker so that they can use an airport's facilities.

Others might offer sex in exchange for a bed. Anything to avoid the manifold dangers of sleeping out at night, when they might be subjected to physical, verbal or sexual attack.

"There is very limited information available about women's rough sleeping," Moss says. "Current data tends to focus on the problem as experienced by men and the hidden nature of women's homelessness can often result in their needs being overlooked. Many homeless women spend time living with friends or relatives with periods of sleeping rough in between."

It is a shock to learn that a homeless woman's life expectancy is halved. A homeless woman can expect to live to around 39 to 40 years old whereas the national average for a woman in Britain is 83 years old.

For a man, it is 44 within the homeless community and 79 among the general population. It is worth remembering that women traditionally live longer than men.

This month sees Crisis, the national charity for single homeless people, open its five residential rough sleepers' centres in London from December 22-30.

These centres will offer meals, a place to sleep and some festive cheer round the clock. One of them is reserved for women.

Every day is tough if you are a homeless woman but St Mungo's says that there is hope, despite the many obstacles to overcome along the way.

Murphy says: "We know what works for these women but the help has to come at the right time and place. As one woman said to me, 'why would I go and meet a drug dealer if I knew my child was safe'?"