One in six privately rented homes in England are physically unsafe, it has been claimed.
Citizens Advice, in a new report called A Nation of Renters, alleges that landlords are earning £5.6bn a year from renting out dangerous homes.
It also says the private rented sector is the most important of all consumer markets, and is calling for action, including a national landlords register.
The report claims there are almost three times the number of unsafe homes in the private market than in the social sector – 16% compared with 6%.
The report says that 740,000 households in England live in unsafe private rental homes, with problems including rat infestations and damp.
Unsafe properties are those with a Category 1 hazard with the most common hazard being risks of falls, found in 440,000 properties, or 10%, of private rented homes.
This was followed by excessively cold properties, which made up 280,000, or 6% of all private rental homes.
Some 8% of properties were found with serious damp problems.
Citizens Advice says that tenants living in homes with a Category 1 hazard typically pay £157 per week rent.
The organisation is calling for urgent action to protect tenants, including entitlement to rent refunds.
It is also calling for a national landlord register, and for more councils to set up local licensing schemes.
The report says: he report said: “When we put together a rapidly expanding sector, poor standards and high prices, we see the true financial cost of a broken sector. In other consumer markets, failures like this would trigger consumer rights to refund or redress.
“As things stand, the housing market, the most important consumer market of all, is lagging far behind.”