Advisers at Shelter's national helpline are doing everything they can to make the call-centre office feel like a cheerful environment. Tinsel with Christmas baubles has been hung from the ceiling, tiny silver Christmas trees and felt reindeer have been stuck on the tops of computer screens, cotton-wool icicles are hanging from the windows, and colleagues have brought in mince pies and chocolates to share.

You quickly understand why maintaining a good mood in the office is important if you spend time listening in to the calls that come in, at a rate of around 500 a day, from people facing imminent homelessness or already sleeping rough and seeking advice about how to find somewhere new to live.