Its survey, conducted by YouGov, found that 41% of tenants, or 3 million people, have tried to talk to their landlords about problems, but the landlord did nothing.
In addition, 7% (550,000 people) did not confront their landlord because they were scared of the consequences.
With the number of people living in rented homes rising 40% in the last five years to 3.4 million, Shelter said it is concerned that cuts in housing benefit will force vulnerable families into the bottom end of the private rented sector targeted by a minority of rogue landlords.
The survey showed that 66% of respondents, or 31.1 million people, believe there needs to be stronger and clearer rules to protect private tenants.
Shelter’s research comes on the eve of a Channel 4 Dispatches documentary investigating the “shocking treatment” of tenants by rogue landlords, highlighting how private tenants are cheated by landlords renting out dirty and dangerous properties.
Campbell Robb, chief executive of Shelter, said: “It’s wholly unacceptable that people are left to live in conditions like those exposed in today’s programme.
“We urge the Housing Minister to work closely with all local authorities and ensure they are using every weapon in their armoury to crack down on unlawful operators, like those exposed in Dispatches.”
A National Landlords Association (NLA) spokesperson said: “The NLA has long called for action to target the small minority of rogue landlords who bring the private-rented sector (PRS) into disrepute.
“Government figures show between 2008 and 2009 the number of ‘non-decent’ homes in the PRS actually fell by 450,000. The NLA aims to raise standards across the sector and will continue to work with local authorities and government to build on that momentum.
“The NLA believes local authorities have a key role to play in using the powers they have to deal with rogue landlords, but they must be properly resourced to do so.
“This is becoming increasingly important, as the PRS plays a greater role in providing accommodation to ease the housing crisis.”
Landlords from Hell, presented by Jon Snow, will be shown tonight at 8pm on Channel 4.
