The 1988 Housing Act aimed to revive the dwindling private rented sector but in the historic spa town it has been the affluent and luxury end of the market that has flourished in the 1990s, Janice Ross and John Robb of Bath College of Higher Education told the conference.
New lets for the cheaper rooms and bedsits, which are needed by people who are young or single and on low incomes, had declined.
The act was intended to revive the collapsing private rented sector by a measure of deregulation, giving landlords more freedom and the prospect of a greater return on their capital. The Government, in common with many housing experts, believed that constraints on the market had encouraged landlords to sell-up.
The hope was that liberalisation would drastically increase the supply of rented homes, benefiting everyone, including the people who could not afford to buy homes or were not eligible for council or housing association property.
The Bath researchers relied mostly on an analysis of advertisements for lets in the city's evening newspaper between 1991 and 1994. They found rents went up by 27 per cent during those four years at a time when house prices were in decline.
The supply of flats and houses, which cost more than £300 a month to rent, grew markedly.
Much of this expansion was because homeowners who moved and did not want to sell their properties in a falling market put them up for rent instead.
The researchers said their findings boded ill for people who depended on the private rented market, especially with plans to cap housing benefit.
The more affluent, leafy suburbs are the ones that offer greatest scope for redevelopment and are changing most rapidly, said Christine Carr, a geography researcher of Birmingham University.
Surveys in Birmingham, London and elsewhere had indicated that the conversion of houses into flats and the building of new homes in gardens was happening more rapidly in the less densely populated suburbs.