Crisis said the recession had hit the poorest hardest
The charity Crisis has set up nine temporary centres in London to help the homeless over the Christmas period.
The centres will provide companionship, food and access to vital services for up to 2,000 homeless and vulnerable people living in accommodation.
More than 8,000 volunteers will take part in the initiative, which also includes a centre in Newcastle.
To mark the opening, Michelin-starred chef Angela Hartnett will cook chilli con carne for 200 homeless people.
As well as providing warm meals and accommodation for rough sleepers, Crisis Christmas tackles the year-round problem of homelessness by linking people to services.
The charity also published results of a survey which found that 75% of the public wants the government to address the growing gap between rich and poor.
A YouGov poll showed that most people in the UK - 60% of those with an opinion - said the recession had made them more worried about the gap.
Leslie Morphy, Crisis chief executive, said: "The British public wants action to address the gap between rich and poor.
"In a country of 242,000 millionaires, nothing highlights the stark contrast more than the homeless people we will welcome to our centres this Christmas.
"This recession has hit the poorest hardest and the British public is not prepared for them to bear the brunt of any public spending cuts."
Crisis is calling for all main political parties to commit to ending homelessness, protect spending on social programmes and tackle poverty, including that of single people, not just families.
The YouGov survey was carried out online from 15-17 December. The total sample size was 2,100 adults.