Thousands of people in London are giving up their time over the Christmas break to work with the homeless.
About a third of people helped by Crisis are rough sleepers
The charity Crisis officially launches its annual Crisis Open Christmas scheme on Tuesday.
Five shelters will be open for the next seven days, looking after an estimated 1,200 homeless people.
They will be offering a range of services, including medical, study courses and other advice.
Crisis says about a third of its guests are sleeping rough and the rest live in hostels, emergency bed and breakfast, in squats or sleep on friends' floors.
More than 3,000 people volunteer their time to help provide the services, which include activities and workshops.
The charity's chief executive Shaks Ghosh told BBC London 94.9 that the most important thing for homeless people was to have company.
"A lot of homeless people are very lonely at this time of year," she said.
"A lot of them, when they are with us, will see the Samaritans. We know there is a very high level of mental illness and depression among them, so the opportunity to be among 3,000 young, vibrant, happy volunteers is something that makes a really big difference."
The Open Christmas scheme began more than 30 years ago when a band of volunteers came together to serve food and provide beds and shelter to homeless people.
Now there is a main shelter in south London, a women's shelter and a quiet shelter for people who need a calm environment.
There is also a specialist shelter for people coping with alcohol addiction.