https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/352350/hbrf_fr_sep14_Final.pdf

DWP stats just released show that

The total Great Britain (GB) value of Housing Benefit (HB) overpayments
outstanding at the beginning of Q4 (2013 /14 ) stood at £1.38
billion; an increase of 9% on this point the previous year.

The total GB value of HB overpayments identified during the whole of 2013/14 has increased by 5%, in comparison to 2012/2013.

The total GB value of HB overpayments recovered during the whole of 2013/14 has increased by 4%, in comparison to 2012/2013.

HBINFO would suggest that the total amount of outstanding HB obverpayment is in fact nearer 2 billion (based on actual fieldweek with a large number of LA’s). Even so, these figures suggest that LA’s are unable to keep up with recoveries.