VoiceMail4All offers a service for people living on the street who have no access to a phone.
A homeless charity has been hailing the success of its landline service which has recently seen its 2,000th member sign up.
VoiceMail4All, created by London charity St Mungo's, provides a free 0209 voicemail number which people who do not have a permanent home can use to make appointments and find work. Users are given a 0800 number which they can use to pick up messages from other landlines or phone boxes.
One user, who gave his name as John, said that the landline number had been particularly helpful when he had been looking for work. He is now working as an accountant.
"Most employers want to know your landline so having a number to put on my CV has been very useful," he explained. "Most employers ring the landline first before calling the mobile. They do often leave messages."
Charles Fraser, chief executive of St Mungo's, added: "Having a phone number can make a huge difference in rebuilding relationships, finding a home, keeping hospital or doctor's appointments, even getting a job or not."
Home repossessions and unemployment are both expected to rise as the recession continues in the UK. Official GDP figures for the fourth quarter of 2008 - the latest available - tracked a 1.6 percent fall in output.
This is the single sharpest decline measured for the UK economy since the early 1980s.
