The surge in private tenants reported in the latest census highlights the need for immediate Government intervention.
The call has come from the Association of Residential Letting Agents, which says that ministers must now act to license letting agents.
Alongside a drop in the proportion of UK owner occupiers to 64%, the proportion of tenants renting privately has increased from 9% to 15%.
Ian Potter, ARLA managing director, said: “The census data confirms what our members have already told us, that would-be home owners are increasingly turning to the private rented sector after being priced out of buying their own property.
“As the private rented sector continues to expand, it is imperative that the Government takes decisive action on regulating letting agents. This will help prevent less scrupulous landlords from taking advantage of the unprecedented level of consumer demand.
“Renting should be a positive experience for both tenant and landlords, and a professional agent will be able to guide them both through the process.”
He added: “In the absence of regulation, we would always advise tenants to rent their properties through an ARLA member agent.”