The price hikes have been exacerbated by a shortage of supply and, in London, the problem is even more acute with rents up nearly double the national average to £1,465 and the average length of tenancy increased from 12 to 18 months as renters are priced out of the sales market, the report said.
With the decline in slavery at the end of the Merovingian era, the number of tenancies increased, and tenants were compelled to render significant amounts of labour to cultivate land held directly by the lord.
But even taking that into account, he told the BBC: "If you roll that out to 31,000 tenancies we will be increasing our bad debt provision by a further £2-3m a year".
Rising populations meant increasing land values, especially for small tenancies.
In addition to increasing rents, many associations are introducing new tenancies where those paying the higher rent have fewer rights and reduced security of tenure.
Increasing in stages up to 50% for a tenancy of 20 years.
The end to lifetime council tenancies, the pay-to-stay rule increasing rents for council tenants earning more than £40,000, and provisions to force local authorities to sell off their high-value homes, will effectively kill off council housing.
Landlords would be banned from evicting tenants as a quick way of increasing rental income with the introduction of three-year tenancy agreements with strict rules.
Ministerial backing for the bill came amid concern over increasing levels of homelessness fuelled by housing shortages, rising rents, insecure tenancies and cuts to housing benefit.
As well as increasing eligibility for social housing and providing for security of tenure in residential tenancies legislation, Sharam and her co-authors recommended introducing measures to ease the pressure in the property market.
