http://www.familymosaic.co.uk/documents/FM_MSM_final_interactive_2up.pdf
"Based on this research, at 80% MR the weekly housing benefit bill
for these tenants would rise from £3,155 to £7,911, an increase of 151%.
Based on this research, at 60% MR the weekly housing benefit bill
for these tenants would rise from £3,155 to £5,286, an increase of 68%.
Based on this research, at 80% MR, the yearly housing benefit bill –
just from these 50 properties – would increase from £164,060 to £411,372".
DWP views on this are here:
http://www.dwp.gov.uk/docs/social-sector-housing-under-occupation-wr2011-ia.pdf