(NHF) study said the increase was due to a big rise in the number of private tenants claiming housing benefit.
The NHF said this particular group of people had grown by 42% since 2008.
In 2006, some £4.6bn in housing benefit was paid to private landlords, a figure which had more than doubled by 2015.
NHF chief executive David Orr said: “It is madness to spend £9bn of taxpayers’ money lining the pockets of private landlords rather than investing in affordable homes.”
“The lack of affordable housing available means that a wider group of people need housing benefit,” he added.
Working poor
Had these housing benefit claimants been living in social housing instead of renting from private landlords, taxpayers would have saved huge sums of money over seven years, the NHF report estimated.
It said that taxpayers paid £1,000 more per year, per family renting in the private rented sector, than they did for those in social housing.
This amounted to an average of £2.2bn a year extra being handed over to private landlords, at a cumulative additional cost of £15.6bn over the past seven years, the NHF analysis says.
If this extra housing benefit bill for just one year had been spent on creating new affordable housing, the NHF added, then nearly 50,000 new homes could have been built.
The report also points out that a larger proportion of families claiming housing benefit in the private rented sector are now in work.
“Today, nearly half (47%) of all families claiming housing benefit in the private rented sector are in work – this is nearly double the proportion it was six years ago (26%),” the NHF said.
‘Tenants failed’
A government spokesman said it had been taking action to bring the housing benefit bill under control.
He said: “Since 2012 the amount going to private sector landlords has actually been falling – something which the National Housing Federation fails to recognise.”
“We are also committed to building the homes this country needs and investing £8bn to build 400,000 more affordable homes.”
