Malcolm Wicks MP, the then Secretary of State for Work and Pensions, said on the 19th December 2001:

"The under-occupation pilot encourages housing benefit recipients living in under-occupied social housing to move to smaller and cheaper accommodation in order to make more efficient use of housing stock."

http://www.publications.parliament.uk/pa/cm200102/cmhansrd/vo011219/text/11219w19.htm

I think Labour need to be reminded of this next time they have a little cry.

I also appreciate that the 'bedroom tax' isn't in any way a tax, but that's what they've chosen to call it so it makes sense to use it in this instance.

Hmmm, interesting...